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MODEL AEROPLANES 

AND THEIR ENGINES 


* 





\ 


Waid Carl’s model in flight 

Courtesy Edward P. Warner, Concord Model Club 









MODEL AEROPLANES 

AND THEIR ENGINES 


A Practical Book for Beginners 

BY 

GEORGE A. CAVANAGH 

Model Editor “Aerial Age” 


DRAWINGS BY 

HARRY G. SCHULTZ 

PRESIDENT THE AERO-SCIENCE CLUB OF AMERICA 


WITH AN INTRODUCTION BY 

HENRY WOODHOUSE 

Managing Editor "Flying” 
Governor of the Aero Club of America 


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NEW YORK 

MOFFAT, YARD & COMPANY 

1917 



^ _ <D 


Copyright, 1916, By 
MOFFATT, YARD AND COMPANY 
NEW YORK 


All rights restrved 
Reprinted August, 1917 


JUN 271918 





TO 

M. T. H. 


/ 


I 


INTRODUCTION 


History tells us—what some of us luckier 
ones heard the Wright Brothers themselves 
tell—that the Wrights’ active work in aero¬ 
nautics was a result of the interest aroused by 
a toy helicopter presented to them by the Rev¬ 
erend Bishop Milton Wright, their father. 

Tremendous developments have taken place 
in aeronautics and aircraft are fast developing 
in size, speed, and range of action. They 
have revolutionized warfare, and seem to be 
destined to become a most important factor in 
the reconstruction that will follow the war. 

The greater the development the truer the 
fact that model aeroplanes may be instru¬ 
mental in bringing to aeronautics men who 
may make valuable contributions to aeronaut¬ 
ics. As a matter of fact, there are already 
in active life, contributing their share to the 
development of aeronautics, young men who 
only a few years ago competed for prizes 


INTRODUCTION 

which the writer offered for model competi¬ 
tion. 

The young men who are now flying models 
will live in the new age—and they have much 
to give and much to receive from it. 

Through the tremendous strides forward of 
aeronautics there are wonderful possibilities 
for the employment of ingenuity, genius and 
skill, and business opportunities, as great as 
have ever been created by progress in impor¬ 
tant lines of human endeavor. Problems of 
engineering as huge as were solved by master 
builders; juridical and legal questions to be 
decided as stupendously difficult as any Glad¬ 
stone would wish them; possibilities for the 
development of international relations greater 
than were ever conceived; problems of trans¬ 
portation to be solved by the application of 
aircraft, as wonderful as any economist could 
wish; opportunities to gain distinction splen¬ 
did enough to satisfy the most ambitious 
person. 

Henry Woodhouse. 

New York, June 5 th, 1916 . 



LIST OF CONTENTS 


PAGE 

Introduction . ix 

History of Model Aviation .i 

Construction.8 

Propellers—Wings—Frame— Assembling— Launching 
Chassis—Pontoons—Launching an R. O. G. or Model 
Hydroaeroplane. 

World Record Models.52 

Lauder Distance and Duration Model—Hittle Tractor 
Hydro—La Tour Flying Boat—Cook No. 42 Model— 
Alson H. Wheeler Twin Pusher Biplane—Rudy Funk 
Duration Model. 

A Model Warplane. 83 

Compressed Air Engines.85-93 

A Single Compressed Air Engine—Wise Com¬ 
pressed Air Engine—Schober-Funk Three Cylin¬ 
der Engine—The Schober Four Cylinder Opposed 
Engine. 

Compressed Air Driven Models.94-102 

The Dart Compressed Air Driven Model—The 
McMahon Compressed Air Driven Monoplane— 

The McMahon Compressed Air Driven Biplane. 

Gasoline Engines—Jopson—Midget Aero Gasoline 

Engine.110-117 

Steam Power Plants.118-122 

H. H. Groves Steam Power Plants—G. Harris’s 
Steam Engine—Professor Langley’s Steam En¬ 
gine—French Experiments with Steam Power 
Plants. 

Carbonic Gas Engine.123-124 

The Formation of Model Clubs.125-138 

World’s Model Flying Records.139-141 

Dictionary of Aeronautical Terms .142-152 















LIST OF ILLUSTRATIONS 


PAGE 

Model Aeroplane in Flight. Frontispiece 

First Model Aeroplane Exhibition.Opp. 4 

Propellers (Diagram 1).9 

How to cut propellers (Diagram 2).n 

Designs for propellers (Diagram 3).14 

Designs for propellers (Diagram 4).17 

Wing construction (Diagram 5) . . ,.20 

Members of the Aero Science Club.Opp. 22 

Members of the Milwaukee* and Illinois Model Aero 

Clubs.Opp. 22 

Frame construction (Diagram 6).25 

Model Assembly (Diagram 7).30 

C. W. Meyer and Wm. Hodgins exhibiting early type 

models.Opp. 32 

Henry Criscouli with five foot model.Opp. 32 

Schultz hydroaeroplane.Opp. 32 

Rubber winder (Diagram 8).35 

Chassis construction (Diagram 9).38 

Pontoon construction (Diagram 10) .43 

Obst flying boat.Opp. 44 

McLaughlin twin tractor hydroaeroplane .... Opp. 44 

Louis Bamberger hydro about to leave water . . Opp. 44 

E. B. Eiring and Kennith Sedgwick Milwaukee Club. 

How to launch R. O. G. model.Opp. 48 

Waid Carl, Concord Model Club. Launching R. O. G. 

model.Opp. 48 

Wallace A. Lauder model (Diagram 11).54- 

Lauder distance and duration model.Opp. 56 

Lauder R. O. G. model.Opp. 56 




















LIST OF ILLUSTRATIONS 

PACK 

Lindsay Hittle world record hydroaeroplane (Diagram 12) 61 

La Tour Flying Boat (Diagram 13).66 

Ellis Cook R. O. G model (Diagram 14).73 

Funk duration model (Diagram 15).78 

Rudy Funk speed model.Opp. 80 

McMahon and Schober compressed air driven models Opp. 80 
Alson H. Wheeler twin pusher biplane .... Opp. 82 

C. V. Obst tractor.Opp. 82 

Model Warplane.84 

Simple compressed air engine (Diagram 16).87 

Schober compressed air driven monoplane . . . Opp. go 

Schober compressed air driven biplane .... Opp. go 

Dart compressed air driven model.95 

John McMahon and compressed air driven mono¬ 
plane .Opp. 98 

Frank Schober preparing model for flight . . . Opp. 98 

John McMahon pusher biplane (Diagram 17) .... 102 

Wise compressed air engine.Opp. 104 

Schober-Funk five-cylinder rotary engine .... Opp. 104 

Schober four cylinder engine (Diagram 18).107 

Jopson gasoline engine.Opp. 108 

Sectional view of Jopson engine (Diagram 19) . . . .112 

Power curve of Jopson engine (Diagram 20) . . . .115 

Midget gasoline engine.Opp. 116 

English steam power plant.Opp. 120 

V. E. Johnson steam driven hydroaeroplane . . Opp. 120 

English compressed air driven biplane.Opp. 122 

Tractor hydroaeroplane fitted with steam power plant . 

.Opp. 122 

English compressed air engine fitted with simple speed¬ 
ometer .Opp. 122 

The Rompel six-cylinder carbonic gas engine . . Opp. 124 
















MODEL AEROPLANES 


HISTORY OF MODEL AVIATION 

Model aeroplaning, as a sport, was first in¬ 
troduced in America during the year of 1907. 
It was then that the first model aeroplane club 
in America was formed by Miss E. L. Todd, 
with the assistance of Mr. Edward Durant, 
now Director of the Aero Science Club of 

America. Prior to this the model aeroplane 

% 

was considered an instrument of experimenta¬ 
tion or, when built to resemble a full sized 
machine, was used for exhibition purposes. 
Noted scientists, men such as Maxim, Langley, 
Eiffel and others, depended largely on models 
to bring about the desired results during their 
experiments. Before the Wright Brothers 
brought forth and launched the first heavier 
than air machine their experiments, to a great 


2 


MODEL AEROPLANES 


extent, were confined to model aeroplanes. 
There is little doubt but that a large majority 
of aviators engaged in flying machines in dif¬ 
ferent parts of the world were at one time in 
their career interested in the construction and 
flying of model aircraft, and from which no 
doubt they obtained their initial knowledge of 
the aeroplane, in so far as the same principles 

and laws apply to any aeroplane, regardless of 
its size. 

The first model aeroplane club went under 
the name of the New York Model Aero Club 
and during its existence a great many of its 
contests were carried on in armories. The 
reason for this was because of the fact that the 
greater number of the models prevalent at that 
time were built along the lines of full sized 
machines, and their manner of construction 
was such as to interfere with the flying ef¬ 
ficiency of the model. Streamline construction 
was something unknown to model constructors 
in those days and, in consequence, crudely con¬ 
structed and heavy models were very often evi- 


HISTORY 


3 


denced, and, as a result, flights of over one 
hundred feet were very seldom made. At about 
the same time model enthusiasts in both Eng¬ 
land and France were actively engaged in con¬ 
structing and flying models, but the type of 
model used was of a different design from those 
flown by the American modelists and as a re¬ 
sult of this innovation many of the early rec¬ 
ords were held abroad. The type of model 
flown by the English modelists resembled in ap¬ 
pearance the letter “A,” hence the term “A” 
type. 

It was not long after the introduction of this 
type of model in America that model aero- 
planing as a sport began to assume an aspect of 
great interest. Models were constructed along 
simpler lines and with a greater tendency 
toward doing away with all unnecessary parts, 
thus increasing the flying qualities of the 
models. Flights of greater distance and dura¬ 
tion were the objects sought and, in their efforts 
to achieve them new records were made at most 
every contest, until flights of from 500 to 1000 


4 


MODEL AEROFLANES 


feet were common occurrences. By the use of 
the A type model and the single stick model 
which made its appearance shortly after the A 
type model, American modelists succeeded in 
breaking most of the world records for this 
type of model which is now termed by English 
modelists “flying sticks.” 

One by one model aeroplane clubs were 
formed in different parts of the country until 
to-day there are in existence about twenty-five 
clubs and all with memberships of from two to 
eight times that of the first model aero club. 
The work which was started by the New York 
Model Aero Club is now being carried on by the 
Aero Science Club of America and its affiliated 
clubs. The interest in model flying grew to 
such an extent that during the year of 1915 the 
Aero Club of America decided to hold the First 
National Model Aeroplane Competition for the 
purpose of offering to the young men of Amer¬ 
ica an opportunity of becoming acquainted 
with this new sport and its advantages. The 
results of this competition were beyond expec- 



First model aeroplane exhibition held at Boston, 1910 







HISTORY 


5 


tation. Models were made capable of flying 
distances and with durations that, to the 
early flyers, seemed impossible. In the hand 
launched contests models were flown for dis¬ 
tances ranging from 2000 to 2500 feet, the win¬ 
ning flight being 3537 feet, and it might also 
be said that the contestant who flew this model, 
with a model of the same design established a 
duration record of 195 seconds. As this goes 
to press, information is received that the 
World's Record for distance for hand launched 
models has been broken by Thomas Hall, of 
Chicago, Ill., an Illinois Model Aero Club mem¬ 
ber, with a flight of 5337 feet. Another in¬ 
teresting result of the competition was the es¬ 
tablishing of a world hydroaeroplane record by 
a member of the Illinois Model Aero Club with 
a model of the tractor type, a four-bladed pro¬ 
peller being used in connection with the model. 
The flying boat which is a late advent to the 
field of model flying also proved a record 
breaker in this competition, having remained in 
the air after rising from the surface of the 


6 


MODEL AEROPLANES 


water, for a duration of 43 seconds. This 
model was flown by a member of the Pacific 
Northwest Model Aero Club of Seattle, Wash¬ 
ington. The establishing of these records 
clearly indicates the advantage of scientific de¬ 
signing and construction and careful handling. 

So satisfactory have been the results of the 
First National Model Aeroplane Competition 
that the Aero Club of America has made ar¬ 
rangements for holding the Second National 
Model Aeroplane Competition during the 
year 1916. But in the announcement of the 
Second National Competition the Aero Club of 
America has made provision for the holding of 
contests for mechanically driven models, in 
view of the interest which is being shown by 
model flyers in the construction of models 
more closely resembling large machines to be 
driven by compressed air, steam and gasoline 
power plants. This is the outcome of a desire 
on the part of model constructors to substitute 
for what is now commonly known as the “flying 
stick,” models more closely resembling large 


HISTORY 


7 


machines, which models can be more satisfac¬ 
torily flown by the use of compressed air, steam 
or gasoline power plants. As in the early days, 
the best flights made by models using com¬ 
pressed air and steam have been made by Eng¬ 
lish flyers, the duration of the flights ranging 
anywhere from 25 to 50 seconds. 

Whether or not the American flyers will re¬ 
peat history and achieve greater results with 
this type of model motive power is something 
that can only be determined in the future. But 
in any event the scientific mechanically driven 
model will, without doubt, assume an important 
position in the field of model aviation. 


CONSTRUCTION 


PROPELLERS 

Propellers may be cut from various kinds 
of wood, but the most suitable, from every 
standpoint, is white pine. The advantage of 
using this wood lies in the fact that the propel¬ 
lers may be cut more rapidly and when cut are 
lighter than those made from most other kinds 
of wood. When coated with the proper kind 
of varnish they are sufficiently strong for or¬ 
dinary flying. Wood selected for propellers 
should be free from knots, holes and other im¬ 
perfections and it is very desirable that it 
should be of perfectly straight grain. 

A piece of such clear white pine 8" long, i" 
wide and Y\ f thick should be selected and on 
one side marked Top. A tracing of the pro¬ 
peller similar in design to Figure I, should be 
laid on this piece of wood and an imprint of the 

propeller design drawn on the Top side. To 

8 


CONSTRUCTION 


9 



Diagram I 















































































IO 


MODEL AEROPLANES 


find the center of the block two lines should be 
drawn from the opposite corners, their point of 
meeting being approximately in the center— 
near enough for all practical purposes to insure 
greater accuracy. Similar lines should be 
drawn from the corners on the Bottom side of 
the block of wood. A hole 3-32 of an inch in 
diameter should be bored through the center 
thus obtained, through which the propeller 
shaft will be inserted when the propeller is 
finished. The two sections of the propeller 
blades drawn in diagrammatical form on the 
Top of the block, should be marked respec¬ 
tively Blade i and Blade 2, as shown in 
diagram 1. The block is then ready for the 
commencement of the actual cutting. In cut¬ 
ting out the propeller, Blade i should be held in 
the left hand and the knife in the other, with 
the blade of the knife on the straight edge of 
Blade i. The cutting should be carried out 
very carefully with attention constantly paid to 
Fig. 2, and should be stopped when the line 
shown in Fig. 2 has been reached. The semi- 


CONSTRUCTION 


it 



Diagram 2 











































































































12 


MODEL AEROPLANES 


blade should then be sandpapered until a small 
curve is obtained by which the propeller will be 
enabled to grip the air. 

To cut Blade 2, Blade i should be held in 
the left hand and Blade 2 cut until the line 
shown in Fig. 3 is reached, after which the 
sandpapering process is carried out in the same 
manner as in the case of Blade i. During all 
of the foregoing operations it must be clearly 
borne in mind that the Top of the blank pro¬ 
peller must always face upward, and the cutting 
should always be done on the Straight lines. 
Should the straight edge be cut 011 one edge of 
the blank propeller and the curved edge on the 
other, it would result in the blades of the 
finished propeller having a tendency to push in 
opposite directions and in consequence no pro¬ 
pulsion of the model would be possible. 

Attention should next be turned to the back 
of the propeller blank on which the manner of 
cutting is exactly like that suggested for the top 
side, with the exception that instead of cutting 
along the Straight lines, the cutting is done 


CONSTRUCTION 


13 


along the Curved lines. In this part of the 
work great care is to be exercised for by the 
time the necessary cutting has been done on the 
back of the propeller the entire structure is very 
fragile and one excessive stroke of the knife 
may result in destroying the entire propeller 
blade. By constantly holding the wood to the 
light it is possible to determine with a reason¬ 
able degree of accuracy the evenness of thick¬ 
ness. To complete the Bottom side of the pro¬ 
peller the blade should be sandpapered as was 
the top. 

The method of cutting the second propeller 
is exactly that used in cutting the first propeller, 
only that the diagram shown in Fig. 4 should be 
used. This will result in two propellers being 
made that will revolve in opposite directions in 
order to produce even and balanced propulsion. 
If both propellers revolved in the same direc¬ 
tion the effect would be to overturn the model. 

In diagram 1 the propellers are shown with 
the straight edge as the entering or cutting 
edge of the blade. Some of the model builders 


14 


MODEL AEROPLANES 



PB<xrJt_er Propeller 


ftamlerger 

Propeller 



Propeller 


Diagram 3 








































CONSTRUCTION 


15 


prefer the curved edge as the cutting edge 
(diagram 2). It is significant that Mr. Frank 
Schober, a well known model constructor, 
tested both designs on his compressed air 
driven model, and while both propellers were 
the same in weight, diameter and pitch, the 
one having the straight edge as the cutting 
edge was found one-third more efficient. 

When the propellers have been given a light 
coat of shellac they should be laid aside until 
the assembling of the complete model. 

By following the foregoing instructions a 
simple and effective set of propellers will be 
produced. But in order to vary the experi¬ 
mental practice of the constructor various other 
diagrams, Nos. 3 and 4, illustrating suitable 
designs, are provided and can be made by ap¬ 
plying the above general theory and using the 
diagrams herewith. 

WINGS 

One of the most important considerations in 
the construction of a model is the making of the 


i6 


MODEL AEROPLANES 


wings. To obtain the greatest efficiency the 
wings must be carefully designed, with due at¬ 
tention to whether the model is being con¬ 
structed for speed, duration or climbing ability. 
Attention should be given to streamline con¬ 
struction ; that is, the parts of the wing should 
be so assembled that the completed wing would 
offer the least possible resistance to the air, if 
the best results are to be obtained. 

For the main wing three strips of spruce, 
each 30" in length, two of them being 3-16" x 
Yx" and the third 3-16" x 1-16" are required. 
To make them thoroughly streamline all edges 
should be carefully rounded off and all surfaces 
should be smooth. A strip of bamboo at least 
20" long, J4" wide, y$" thick, should be cut 
into pieces, each piece to be 5 in. long. To 
secure the necessary curve, y/' depth, the 
pieces of bamboo should be held in steam and 
slowly bent in a manner closely resembling the 
skids of an ordinary bob-sled. When the 
curvature has been obtained, care should be 
exercised in cutting each piece into four longi- 


CONSTRUCTION 



Diagram 4 




































































i8 


MODEL AEROPLANES 


tudinal strips, from which twelve should be 
selected to be used as ribs, each to be %" 
wide. The bending of the bamboo preliminary 
to making the ribs is done in order to secure uni¬ 
formity of curvature. 

When this has been done the ribs are ready 
for fastening to the sticks—entering and trail¬ 
ing edges—and each must be attached an equal 
distance apart. In order that the ribs may be 
evenly spaced it is necessary to put a mark 
every 3" on the larger stick or entering edge 
of the wing, and also on the flat stick or trailing 
edge. The main beam which is of the same 
dimensions as the entering edge is afterwards 
fastened across the center of the wing, and does 
not necessarily need to be thus marked, as it is 
fastened to the ribs after the ribs have been 
attached to the entering and trailing edges of 
the wing frame. By holding the ribs one at a 
time so that the curved edge rests upon the en¬ 
tering edge where the mark indicates, as shown 
in diagram 5, they should be fastened thereon 
by means of thread and glue. The rear end of 


CONSTRUCTION 


19 


the rib must be fastened to the trailing edge 
where the mark indicates, also by thread and 
glue. 

After all ribs have been thus securely fast¬ 
ened to both edges of the frame the third stick, 
or main beam, should be attached to the frame 
on the underside, the fastening being made at 
the highest point of the curve of each rib. This 
main beam prevents the wing covering from 
drawing in the end ribs and adds very materi¬ 
ally to the strength of the entire wing struc¬ 
ture. To cover fhe wings fiber paper may be 
used and is a suitable material, but the best re¬ 
sults, from a standpoint of flying efficiency and 
long service, are obtained by the use of China 
silk. 

The frame of the forward wing or elevator 
is made in the same manner as is the main wing, 
but it is only 12" in span by 4" in chord, and 
is constructed without the use of a main 
beam. This wing has only five ribs which are 
made in the same manner as those for the rear 
wing, and each is placed a distance of 3" apart. 


20 


MODEL AEROPLANES 



Diagram 5 
















CONSTRUCTION 


21 


A piece of silk measuring 2" longer and 2" 
wider than each of the wing frames should 
be used in covering the wings, and this can be 
held in position by the use of pins prior to the 
actual sewing. The extra inch of silk on all 
sides of the frame is placed around the under 
side of the frame—in order that it can be made 
thoroughly taut when the silk has been sewn 
close to the edges of the frame. After the silk 
has been sewn close to the edges the pins may be 
removed and the surplus silk that hangs from 
the under side of the frame may be cut off. To 
make this silk airproof it should be coated with 
a thin coat of shellac or varnish and the wings 
should be thoroughly dry before being used. 
This coating, in addition to airproofing, will as¬ 
sist in making the covering perfectly taut, and 
also in making the wing ready for service when 
the entire model is ready to be assembled. 

FRAME 

As all other parts of the model are attached 
to the frame in addition to its having to stand 



22 


MODEL AEROPLANES 


the strain of the tightly wound rubber strands 
which serve as the motive power for the model, 
it must be made strong. It is therefore neces¬ 
sary to exercise care and judgment in making 
certain that the different units that make up the 
frame are rightly proportioned and are of the 
proper material. Just as in the large sized 
aeroplanes there are many types of bodies, so 
there are many different types of frames in use 
in model construction, but the standard, and 
for all practical purposes the best frame, re¬ 
sembles the letter A in shape, hence the name 
A type. The lightness of the frame depends 
entirely on the materials used and the manner 
in which it is constructed. 

Some model flyers use but a single stick for 
the frame, but generally the A type frame is 
preferred for the reason that it is more durable, 
the wings can be more securely attached to it, 
and that it is possible of developing very much 
better results. 

To construct such an A type frame 2 main 
sticks to serve as frame side members are neces- 



Members of the Aero Science Club 



Members of the Milwaukee and Illinois Model Aero Clubs 











CONSTRUCTION 


23 


sary and are made from spruce. Each member 
should be 36" in length, in depth by in 
width. By rounding the edges and smoothing 
the various surfaces with sandpaper streamline 
effect will be secured and will add to the ef¬ 
ficiency of the machine as well as to its appear¬ 
ance. When the side members are placed in A 
formation the extremity of the sticks at which 
they meet should be so tapered in the inner 
sides that when they meet and are permanently 
fastened the result will be a continuance of the 
general streamline effect. The permanent 
fastening of the frame side members at the 
poin£ of the A may be accomplished by using 
either strong fish glue or better, a good water¬ 
proof glue and then have the jointure rein¬ 
forced by securing a piece of 3-32" steel wire 3" 
in length and placing the center of it at the 
point of the A, afterwards bending the wire 
along either outer edge of the frame side mem¬ 
bers, putting as much pressure on the wire as 
the strength of the structure will permit; after 
this the reinforced jointure should have thread 


24 


MODEL AEROPLANES 


wound around it to insure even greater 
strength. About of the wire on each side 
of the point should be left clear and afterwards 
turned into a loop as shown in diagram 6, for 
the purpose of attaching the hooks that hold 
the rubber strands. To hold the side members 
apart at the rear end and for a propeller brace, 
a piece of bamboo io" long, y$" thick by y?" 
in width is required and this should be fastened 
to the extreme rear ends of the frame side mem¬ 
bers, allowing the propeller brace to protrude 
on either side ij 4 " as illustrated. To put the 
propeller brace in position a slot y 2 ” deep by 
]/y r wide should be cut into the rear ends of the 
frame side members for the reception of the 
propeller brace. After the brace has been 
placed in position the outer edge should come 
flush with the rear ends of the side members. 
To hold the brace in place thread and glue 
should be used in the same manner as described 
for the point of the frame side members. Be¬ 
tween the point of the frame and the propeller 
brace two bamboo pieces, one 9" long and an- 


Tnc-m&e-r* 


I 


CONSTRUCTION 2 5 






Diagram 6 









26 


MODEL AEROPLANES 


other 2 1-3" long, should be used as braces for 
the general strengthening of the structure. 
The longest piece should be secured across the 
top of the frame about 9" from the rear and 
the shorter piece about 9" from the point. 

When these two braces are in position the 
next matter that calls for the attention of the 
constructor is the matter of getting into posi¬ 
tion at the two outer extremities of the pro¬ 
peller brace bearings for the propellers. For 
this purpose two pieces of 3~32nd inch brass 
tubing, each 24 th of an inch long, should 
be used, and should be fastened to the under¬ 
side of the propeller brace, at each extremity of 
that brace, by the use of thread and glue. 
Sometimes greater efficiency is secured by put¬ 
ting these pieces of bronze tubing about J4" 
from the end. Some model constructors make 
a very neat jointure here by soldering the piece 
of tubing to a strip of thin brass, which is bent 
over the end of the propeller brace and bound 
and glued thereon. In fastening the bronze 
tubing to the propeller brace it should be so 


CONSTRUCTION 


27 


adjusted that it will run parallel to the side 
members of the frame and will therefore offer 
the least possible resistance to the shaft of the 
propeller when the rubber strands have been 
attached. 

When the frame has been completed a coat 
of shellac should be applied to the entire struc¬ 
ture to render it damp-proof. 

ASSEMBLING 

The proper assembling of the parts of the 
model is as essential to good results as is the 
designing and making. Parts, although prop¬ 
erly made, if improperly placed in relation to 
each other will very often lead to trouble. 
Therefore very great care must be exercised in 
the assembling process. 

When all the parts have been prepared and 
are ready to be assembled the first thing that 
should be done is to mount the propellers in 
position. This must be done very carefully on 
account of the fact that the propeller shafts 
are easily bent and if bent the result is consider- 


28 


MODEL AEROPLANES 


able trouble, for such a bend in the propeller 
shaft will cause the propeller to revolve irregu¬ 
larly with a consequent loss of thrust. Before 
inserting the propeller shafts in the tubing 4 
washers each ^4" * n diameter should be cut 
from hard metal, and a hole large enough for 
the propeller shaft to pass through should be 
bored in the center of each washer. The metal 
washers should be passed over the straight ends 
of the shafts which extend from the rear of 
the tubing, after they have been inserted in the 
tubing, and in this manner the cutting into the 
hubs of the propellers which would follow is 
avoided. The propellers are now to be 
mounted and this is accomplished by allowing 
the ends of the shafts, which extend out from 
the rear of the tubing, to pass through the hole 
in the hub of each propeller. In mounting the 
propellers it is absolutely necessary to have the 
straight edge of the propellers to face the point 
or front end of the model. The propeller 
shown in Fig. 4 of diagram 1, should be 
mounted on the left side of the frame to revolve 


CONSTRUCTION 


29 


to the left, while the propeller shown in Fig. 1 
should be mounted on the right side of the 
frame to revolve to the right. When the pro¬ 
pellers have thus been mounted the one-half 
inch of shafting which extends out from the 
hubs of the propellers should be bent over to 
grip the propeller hub and thereby prevent the 
shaft from slipping during the unwinding of 
the rubber strands. For the reception of the 
rubber strands to provide motive power a hook 
must be formed in each shaft and this can be 
done by holding securely that portion of the 
shaft which extends toward the point of the 
model, while the end is being formed into a 
hook as illustrated in diagram 7. 

Eighty-four feet of J 4 th" flat rubber is 
necessary to propel the model. This should be 
strung on each side from the hooks (see dia¬ 
gram) at the front part of the model to the pro¬ 
peller shafts at the rear of the model. In this 
way 14 strands of rubber will be evenly strung 
on each side of the frame. To facilitate the 
winding of the rubbers two double hooks made 


30 


MODEL AEROPLANES 



Diagram 7 



































CONSTRUCTION 


3i 


of 3-32" steel wire to resemble the letter S, 
as shown in diagram 7, should be made. One 
end of this S hook should be caught on the 
frame hook, while the other end is attached to 
the strands of rubber, and to prevent the pos¬ 
sible cutting of the strands a piece of rubber 
tubing is used to cover over all wire hooks that 
come in contact with the rubber strands pro¬ 
viding propelling power. 

The wings are mounted on the top side of the 
frame members by means of rubber bands and 
in placing them upon the frame it should be 
noted that the entering edge of each wing must 
face the point or front of the model. The 
wings must be so adjusted on the frame that 
they result in perfect side balance which means 
that there is an even amount of surface on 
either side of the model. To secure a longi¬ 
tudinal balance it will be found that the enter¬ 
ing edge of the main wing should be placed 
approximately 8" from the propeller brace or 
rear of the model, and the entering edge of the 
small wing or elevator approximately 6" from 


32 


MODEL AEROPLANES 


the point. But it is only by test flying that a 
true balance of the entire model can be obtained. 
To give the necessary power of elevation 
(or lifting ability) to make the model rise, a 
small block of wood about i" long by 
square must be placed between the entering 
edge of the small wing and the frame of the 
model. 

After the wings have been thus adjusted and 
a short test flight made to perfect the flying and 
elevating ability of the model, and this test 
flight has been satisfactory, the model is ready 
for launching under its full motive power. 

LAUNCHING 

In the preliminary trials of a model close at¬ 
tention must be paid to the few structural ad¬ 
justments that will be found to be necessary 
and which if not properly and quickly remedied 
will result in the prevention of good flights or 
even in possible wrecking of the model. Care¬ 
ful designing and construction are necessary 
but it is equally as important that the model 



Charles W. Meyers and 
William Hodgins exhibit¬ 
ing models of early de¬ 
sign. 


Henry Criscouli and his five 
foot model. This model 
may be disassembled and 
packed conveniently in 
small package 



Harry G. Schultz hydroaeroplane 
















CONSTRUCTION 


33 


should be properly handled when it is complete 
and ready for flying. 

The approximate idea of the balance of a 
model can be secured by launching it gently into 
the air. If the model dives down point first it 
indicates that the main wing should be moved 
a little toward the front. If it rises abruptly 
the main wing should be moved slightly toward 
the rear. In this way by moving the wing for¬ 
ward or rearward until the model glides away 
gracefully and lands flat upon the ground, 
proper adjustment of the balance can be ef¬ 
fected. If when launching from the hand the 
model should curve to the left the main wing 
should be moved slightly to the left of the frame 
members. And if the curve is to the right the 
main wing should be moved in that direction. 
This process can be continued until the model 
flies in the course desired. 

The winding of the rubber strands to get the 
necessary propelling power is an important de¬ 
tail. The model should be firmly held by some 
one at the rear with the thumb on either side 


34 


MODEL AEROPLANES 


member, pressing down on the jointure and 
with the four fingers of each hand gripping the 
under side of the frame members, and in this 
way holding the model steady and until the 
rubber strands have been sufficiently wound. 
With the hands in this position the propellers, 
of course, cannot and should not revolve. The 
hooks attached to the rubber strands at the 
point or front of the model should be detached 
from the side members and affixed to the hooks 
of the winder. A winder may be made from 
an ordinary egg beater as is shown in diagram 
8. When the hooks attached to the rubber 
strands at the point of the model have been 
affixed to the winder the rubbers should be 
stretched four times their ordinary length 
(good rubber being capable of being stretched 
seven times its length) and the winding com¬ 
menced, the person winding slowly moving in 
towards the model as the strands are wound. 
If the ratio of the winder is 5 to i, that is if the 
rubber is twisted five times to every revolution 
of the main wheel of the winder, 100 turns of 


CONSTRUCTION 


35 



Diagram 8 



























































36 MODEL AEROPLANES 

the winder will be sufficient for the first trial. 
This propelling power can be increased as the 
trials proceed. When the winding has been 
accomplished the rubber hooks should be de¬ 
tached from the winder hooks and attached to 
the hooks at the front of the side members as 
shown in the diagram. 

In preparation for launching, the model 
should be held above the head, one hand holding 
it at the center of the frame, the other in the 
center of the propeller brace in such a way as 
to prevent the propellers from revolving. 

. When the model is cast into the air if it is prop¬ 
erly adjusted it will fly straight ahead. 

A precaution which is sometimes worthy of 
attention before the launching of the model 
under its full power is to test out the propellers 
to find out whether or not they are properly 
mounted and whether they revolve evenly and 
easily. To do this the rubber strands may be 
given a few turns, enough to revolve the pro¬ 
pellers for a brief period, while the machine is 
held stationary. If the shafts have been prop- 


CONSTRUCTION 


37 


erly inserted in the hubs of the propellers and 
have not been bent during the winding of the 
rubbers, the propellers will revolve evenly and 
readily. If the propellers revolve unsteadily it 
indicates that there is a bend in the propeller 
shafts or the propellers have not been properly 
balanced. If the trouble is a bend in the shaft, 
it must be removed before the - model is 
launched on actual flight. If the propeller 
does not revolve freely the application of some 
lubrication (such as vaseline) to the shaft 
will eliminate this trouble. With these adjust¬ 
ments made satisfactorily, the model can be 
launched with the anticipation of good flying. 

CHASSIS 

The preceding instructions and discussions 
have dealt with different parts of a simple 
model to be used as a hand-launched type of 
model. The experience which will come as the 
result of flying this type of model for a period 
will undoubtedly tend toward a desire on the 
part of the constructor to make his model more 


MODEL AEROPLANES 




Diagram 9 







CONSTRUCTION 


39 


nearly represent a large sized aeroplane and 
will make him want to have his model rise from 
the ground under its own power. Such a 
model is known as an R. O. G. type, that is, 
rises off the ground. To meet this desire all 
that it is necessary to do is to make a chassis, 
or carriage, which can be secured to the frame 
of the model, and with extra power added, will 
result in a practical R. O. G. model. In con¬ 
structing such a chassis or carriage it is neces¬ 
sary to bear in mind that it must be made suffi¬ 
ciently strong to withstand the shock and stress 
which it will be called upon to stand when the 
model descends to the ground. 

For the main struts of the chassis two pieces 
of bamboo each 9" in length are needed and 
these should be bent over 1" on one end as 
shown in the diagram, that they may be fast¬ 
ened to the under side of the frame members, 
one on either side, at a point on that member 
12" from the front. Two similar pieces of 
bamboo, each piece about 7" in length, are re¬ 
quired to act as braces between the frame mem- 


40 


MODEL AEROPLANES 


bers and the main chassis struts. Each end of 
each of the braces should be bent over in the 
same direction and in the same manner as that 
described for the main strut so that the fasten¬ 
ing to the main frame member and the main 
chassis strut may be accomplished. Steam 
may be used in bending the ends of the pieces 
of bamboo. To make the landing chassis suffi¬ 
ciently stable to withstand landing shocks a 
piece of bamboo 9" should be fastened from 
either side of the main chassis struts at the 
point where the chassis brace on either side 
meets with main strut. The ends of this cross 
brace should be bent in similar fashion to the 
other braces to enable its being fastened easily 
and securely. 

Two small wheels constitute the running gear 
for the front part of the chassis, for which two 
pieces of 1-16" steel wire each 2]/\ r long 
are required. These small wires are fastened 
to the bottom ends of the main struts, and to 
accomplish this the wire should be bent in the 
center at right angles; one leg of the angle is 


CONSTRUCTION 


4i 

attached to the bottom end of the main strut as 
shown in the diagram. Disks for wheels may 
be cut from a bottle cork which should be ^4" 
in diameter by approximately in thickness. 
The edges should be rounded off to prevent 
chipping. Before mounting the wheels on the 
axles which have been provided by the wires at¬ 
tached to the bottom of the main struts, a piece 
of bronze tubing 3-32" inside diameter and 
3-16" long should be inserted in the center of 
each disk. To secure the least possible resist¬ 
ance on the revolutions of the wheels, there 
should be placed on the wire axles pieces of 
bronze tubing similar in diameter and in 
length on either side of the wheel (see illustra¬ 
tion). When the wheel is thus placed in posi¬ 
tion with the pieces of bronze tubing on either 
side about Y\ r of the axle wire will extend from 
the outward end of the outside piece of tubing. 
This should be bent over the tubing to prevent 
its falling off and at the same time hold the 
wheel securely in position. 

For the rear skid a piece of bamboo 6" long 


42 


MODEL AEROPLANES 


is used, one end of which is curved as in a 
hockey stick so that it will glide smoothly over 
the ground. The other end of the rear skid 
should be bent over about so that it can be 
securely fastened to the propeller braces, as il¬ 
lustrated in the diagram. Two 7" pieces of 
bamboo are required to act as braces for the 
rear skid. Both ends of each brace strut are 
bent over y 2 " in the same direction, one end of 
each strut is securely fastened to a side mem¬ 
ber 3" from the rear and the other end of each 
strut is fastened to the rear skid, at their point 
of meeting as shown in diagram 9, the method 
of attaching being the same as in the case 
of the forward portion of the chassis. All 
joining should be accomplished by first gluing 
the braces and then binding with thread. 
When completed, the rear skid should glide 
along the ground in bobsled fashion, thus pre¬ 
venting the propellers from hitting the ground. 

In making such a chassis or carriage the en¬ 
deavor should be made to use, as near as pos¬ 
sible, the same weight of material on either side 


CONSTRUCTION 


43 



SZ /»*« 


TonLoorv Conatrucii^>zv. 


facts' T&rvtoons 


Diagram io 










































44 


MODEL AEROPLANES 


of the model so as little interference as possible 
will be made with the general balance of the 
model in flight. 

PONTOONS 

Having satisfactorily developed the hand 
launched model and the model rising off the 
ground under its own propulsion the construc¬ 
tor will next turn his mind to the question of 
having his model rise under its own power from 
the surface of the water in the fashion of pas¬ 
senger-carrying hydros and flying boats. This 
will be accomplished by the use of pontoons at¬ 
tached to a specially designed chassis. 

Three pontoons are necessary and these 
should be made as light as possible. Each pon¬ 
toon should be made 6" long, i" deep toward 
the forward part, by at the rear and 2" 
wide. The side members of each pontoon are 
made from pieces of thin white pine wood 
1-32nd of an inch thick, slightly curved up at 
the front and sloped down toward the rear. 
Small niches should be made on the top and bot¬ 
tom sides of the pontoons into which the cross 



C. V. Obst World record Twin tractor Hydroaeroplane 
flying boat designed and constructed 

by George F. McLaughlin 



Louis Bamberger’s hydro about to 
leave surface of water 













CONSTRUCTION 


45 


braces are inserted and glued. Further refer¬ 
ence to diagram io will show that at the ex¬ 
treme forward end of the sides a cut is made 
large enough to receive a flat piece of spruce 
1-16" wide. Another cut of the same dimen¬ 
sions is made at the extreme rear end. Still 
further cuts are made on the top and bottom 
sides of the pontoons, the forward cuts meas¬ 
uring ij4" from the front and the rear cuts 
i from the rear, to join the sides of the pon¬ 
toons as illustrated in diagram io. Six pieces 
of 1-16" flat spruce are required for the rear 
pontoon, the ends of which are held in posi¬ 
tion by glue. For the forward pontoon only 4 
braces are required in so far as the ends of the 
two main brace spars of the forward part of 
chassis are inserted in the cuts on the top sides 
of the pontoon. These brace spars measure 10 
inches in length and are made from bamboo 
}ith inch in diameter, which necessitates en¬ 
largement of the cuts on the top sides of the 
forward pontoons so that the extreme ends of 
the spars can be inserted in the cuts in the place 


4 6 


MODEL AEROPLANES 


of the braces. To complete the rear pontoon 
and prepare it for covering, three strips of 
Y&” bamboo are required for struts. Two of 
these strips should measure 9" in length and 
should be attached to the front of the pon¬ 
toon on the inner side as shown in diagram 10. 
.Thread and glue should be used in attaching 
the ends of the strips to the pontoon. To en¬ 
able fastening to the frame the upper ends of 
the bamboo strips should be bent over about 
y 2 ”. The third strip should measure 8" in 
length and is attached to the upper and lower 
braces toward the front of the pontoon as 
shown in the diagram. It is necessary that 
this strip be secured in the approximate center 
of the pontoon to insure a good balance. For 
the purpose of securing the upper end of the 
third strut to the center of the propeller brace 
a piece of wire 1 y 2 ' long should be secured to 
the upper end of the strut and looped as shown 
in diagram 10. The three pontoons should 
now be covered with fiber paper and it is neces¬ 
sary to exercise care to avoid punctures. For 


CONSTRUCTION 


47 


the purpose of coating the fiber paper to render 
it waterproof, a satisfactory solution can be 
made by mixing banana oil with celluloid until 
it has attained the desired thickness, after 
which it should be applied to the covering of 
the pontoons with a soft brush. 

For the main strut of the forward portion of 
the chassis two pieces of bamboo, each 
11" in length, are required and these should 
be bent over i" on one end as shown in the 
diagram, that they may be fastened to the un¬ 
der side of the frame members, one on either 
side at a point on that member n" from the 
front. Two similar pieces of bamboo, each 
piece 8" in length, are required to act as braces 
between the frame members and the main 
chassis struts. Each end of the braces should 
be bent over in the same direction and in the 
same manner as that described for the main 
struts so that the fastening to the main frame 
member and the main chassis struts may be 
accomplished. Steam or an alcohol lamp may 
be used in bending the ends of the pieces of 


4 8 


MODEL AEROPLANES 


bamboo. To make the chassis sufficiently 
stable a piece of bamboo 7J4 " should be fast¬ 
ened from either side of the main chassis struts 
at the point where the chassis brace on either 
side meets With the main strut. The ends of 
this cross brace should be bent in similar fash¬ 
ion to the other braces to enable its being 
fastened easily and permanently. 

For the accommodation of the pontoons two 
strips of flat steel wire, each 4" in length, 
should be attached to the ends of the main 
struts, about one inch from the bottom, the 
farthest ends should be bent to grip the second 
spar which joins the pontoons. Note diagram 
10. 

To further strengthen the chassis a strip of 
flat steel wire sufficiently long enough should be 
bent so that Yz" of the central portion can be 
securely fastened to the center of the cross 
brace as shown in diagram 10. The two 
outer ends should be bent down and are fas¬ 
tened to the wires which are attached to the bot¬ 
tom ends of the struts. This method of at- 



Erwin B. Eiring about to release R. O. G. Model. (Note 
manner of holding propellers.) Kennith Sedgwick, tractor 
record holder Milwaukee Model Club. Courtesy Gilbert 
Counsell. 



Waid Carl releasing R. O. G. Model. Courtesy Edward 
P. Warner. 















CONSTRUCTION 


49 


taching the forward pontoons enables the con¬ 
structor to adjust them to any desired angle 
and also detach them when not in use. 

A model hydroaeroplane is one of the most 
interesting types of models and if properly 
taken care of will afford the constructor many 
pleasant moments. 

LAUNCHING AN R. O. G. OR MODEL 
HYDROAEROPLANE 

Although the method of determining the bal¬ 
ance of an R. O. G. or a model hydroaeroplane 
is exactly the same as that of a hand launched 
model, the manner of launching is somewhat 
different. Instead of holding the model one 
hand in the center of the frame and the other at 
the rear as in the case of the hand launched 
model, in launching an R. O. G. or hydro, the 
model should be rested upon the ground or 
water, as the case may be, with both hands 
holding tightly to the propellers. Then when 
about to let the model go release both propellers 
instantly. If the model has sufficient power 


50 


MODEL AEROPLANES 


and it has been properly adjusted it will glide 
over the surface of the ground or water for a 
short distance, then rise into the air. Should 
the model fail to rise into the air additional 
strands of rubber should be added, after which 
it should be rewound and a second attempt 
made. 

Should the model fail to respond after the ad¬ 
dition of extra rubber, the indications are that 
something requires further adjustment. Per¬ 
haps the pontoons need further elevation if the 
model is a hydro, or if it be an R. O. G. model 
the forward wing may require an increase of 
elevation. In any event the model should be 
carefully examined and adjustments made 
where necessary, after which the model should 
be tested for balance and elevation. If satis¬ 
fied with the behavior of the model after test 
flights have been made, another attempt should 
be made to launch the model from the ground 
or water. 

On no account try to fly the model in the 
house, or see, supposing the model is of the R. 


CONSTRUCTION 


5i 


O. G. type, if it will rise from the dining room 
floor. This advice may seem unnecessary, but 
it is not so, for there has been quite a number 
of instances in which the above has been done, 
nearly always with disastrous results, not al¬ 
ways to the model, more often to something of 
much greater value. The smashing of win¬ 
dows has often resulted from such attempts, 
but generally speaking pictures are the worst 
sufferers. It is equally unwise to attempt to 
fly the model in a garden in which there are 
numerous obstructions, such as trees and so 
forth. A wrecked model is very often the re¬ 
sult of such experimenting. The safest way to 
determine the flying ability of any model is to 
take it out in an open field where its flight is 
less apt to be interrupted. 


WORLD RECORD MODELS 

1 THE LAUDER DISTANCE AND 
DURATION MODEL 

After many months of experimentation Mr. 
Wallace A. Lauder succeeded in producing a 
model that proved to be one of his most suc¬ 
cessful models. But a few years ago flights 
of iooo feet with a duration of 60 seconds were 
considered remarkable. But so rapid has been 
the development of the rubber strand driven 
model that to-day it is hardly considered worth 
while to measure a flight of iooo feet, espe¬ 
cially in contests where models fly over 2500 
feet or 3537 feet which was the distance flown 
by Mr. Lauder’s model during one of the con¬ 
tests of the National Model Aeroplane competi¬ 
tion of 1915* Mr. Lauder’s model on several 
occasions made flights of over 3500 feet with a 

duration in each event of over 195 seconds. It 

* 

is therefore to be remembered that this model 


52 


LAUDER WORLD RECORD MODEL 53 

is both a distance and duration model, both 
qualities being seldom found in one model. 

Reference to the accompanying drawing 
will give a clear idea of the constructional de¬ 
tails. 

The frame or fuselage consists of two side 
members 40" in length, of straight grained 
spruce. At the center each member is of ap¬ 
proximately cross section, and is ' m di¬ 
ameter. The members taper to about 3-16" at 
the ends, the circular cross section being main¬ 
tained throughout. The frame is braced by a 
strip of bamboo of streamline form, extending 
from one side member to the other, 18" from 
the apex of the frame. The ends of this frame 
are bent to run parallel to the side members of 
the frame where they are secured by binding 
with silk thread and gluing. Piano wire hooks 
are also secured to the side members of the 
frame adjacent the ends of the cross brace, and 
from these hooks extend wires of steel (No. 2 
music wire) which run diagonally to the rear 
brace or propeller spar where they are secured. 


54 


MODEL AEROPLANES 



Diagram n 













































LAUDER WORLD RECORD MODEL 55 


The frame is braced further by an upwardly 
arched strip of bamboo, as shown in diagram 
11, this strip being 2)/i" in height. At the top 
of this brace are two bronze strips of No. 32 
gauge brass, one above the other, one on top of 
the brace and the other below. 

Adjacent the ends of these strips of metal are 
perforations through which pass bracing wires, 
one of which wires run to the front of the 
frame where a hook is mounted for its recep¬ 
tion, and the other two wires extend to the rear 
of the frame where they are secured to the pro¬ 
peller brace. The propeller brace consists of 
a strip of streamlined spruce in length, 

the propellers being at an angle, thus clearance 
is allowed *4” wide at the center, tapering to 
3-16" at the ends. The ends of the propeller 
brace extend out one inch from the side mem¬ 
bers of the frame, to allow room for the rubber 
strands to be used as motive power. In order 
to avoid slotting the ends of the side members 
of the frame so that the propeller brace can be 
secured therein, thin strips of bamboo are se- 


56 MODEL AEROPLANES 

cured above and below the end of each side 
member, by binding with silk thread and glu¬ 
ing, the space between these bamboo strips be¬ 
ing utilized for the brace which is securely 
bound and glued therein. The propeller bear¬ 
ings consist of strips of very thin bronze (No. 
32 gauge), about 3-16" in width, bent over 
5 /$" strips of German silver tubing, the tubing 
being soldered to the bronze strips and the 
propeller brace, which fits between the up¬ 
per and lower portions of the bronze strips, is 
securely bound and glued thereto. 

The propellers are cut from solid blocks of 
pine, and are 12" in diameter. The blade, at 
its widest portion, measures 1 . The blades 

are cut very thin, and in order to save weight, 
they are not shellacked or painted. 

The propeller shafts are of piano wire (No. 
20 size) to fit the tubing used in the bearings, 
pass through the propellers and are bent over 
on the outer side to prevent turning. A few 
small bronze washers are interposed between 
the propellers and the outer ends of the tubing 



Wallace A. Lauder distance and duration model 



Wallace A. Lauder R. O. G. Model 























LAUDER WORLD RECORD MODEL $7 


to minimize friction when the propellers are re¬ 
volving. Twelve strands of rubber are used 
for each propeller, the rubber being y §" flat. 

The wings are both double surfaced, and are 
of the swept back type. The span of the main 
wing is 28*4", with a chord of 6 T / 2 ". The ele¬ 
vator has a span of 15" with a chord of 434". 
The main wing has eleven double ribs, these 
ribs being built up on mean beams of spruce 
1-16" x 3-16", the front beam being placed ij4" 
from the entering edge, and the second beam 
being 2" back from the front beam. The enter¬ 
ing and trailing edges are formed from a sin¬ 
gle strip of thin split bamboo, all the joints be¬ 
ing made by binding with thin silk and gluing. 

The elevator is constructed in like manner, 
except that it only has seven ribs, and the meas¬ 
urements are as above set forth. Both planes 
are covered with goldbeater’s skin, sometimes 
known as “Zephyr” skin, which is first glued in 
place and then steamed, which tightens the 
same on the plane, and given a coat of prepara¬ 
tion used for this purpose. 


THE HITTLE WORLD RECORD 

MODEL 


(single tractor monoplane, 116 seconds 

DURATION RISING FROM WATER) 

The Hittle World record model hydroaero¬ 
plane, designed and constructed by Mr. Lindsay 
Hittle of the Illinois Model Aero Club, is per¬ 
haps one of the most interesting types of models 
yet produced. The establishing of this record 
illustrates the value of careful designing and 
construction and offers to the beginner an ex¬ 
ample which might be followed if good results 
are sought. In having broken the world’s 
model hydroaeroplane record with a tractor 
type model Mr. Hittle accomplished a feat of 
twofold importance. First, in having ad¬ 
vanced the possibilities of the tractor model, 
and, second, in illustrating the value of scien¬ 
tific construction. The previous record for 

58 


HITTLE WORLD RECORD MODEL 59 

this type of model has been but 29 seconds, just 
one-fourth of the duration made by Mr. Hit- 
tie’s model. 

Mr. Hittle’s model shows many new and 
original features not hitherto combined on any 
one model. Note diagram 12. The model is 
of extremely light weight, weighing complete 
but 1.75 ounces. The floats and their attach¬ 
ments have been so designed as to offer the 
least possible wind resistance. In fact every 
possible method was utilized in order to cut 
down weight and resistance on every part of 
the model. As a result of this doing away with 
resistance an excellent gliding ratio of 8^4 to 1 
has been obtained. 

For the motor base of the model a single stick 
of white pine %" deep and 45" in length is used. 
On the front end the bearing for the propeller 
is bound with silk thread and a waterproof glue 
of the constructor’s own composition being 
used to hold it secure. For the bearing a small 
light weight forging somewhat in the shape of 
the letter “L” is used, this being made stream- 


6o 


MODEL AEROPLANES 


line. At the rear end of the engine base is at¬ 
tached a piano wire hook for the rubber. The 
stabilizer consisting of a segment of a circle 
measuring 12" x 8" is attached to the under 
side of the engine base. The rudder measur- 
ing 3^4" x 3^2" is attached to the stabilizer at 
the rear of the engine base. 

The wing is built up of two beams of white 
pine with ribs and tips of bamboo and has an 
area of 215 square inches 

The wing which has a total span of 43" and 
a chord of 5 y§" is built up of two beams of 
white pine with ribs and tips of bamboo and 
has a total area of 215 square inches. The 
wing is given a small dihedral and the wing tips 
are slightly upturned at the rear. 

The trailing edge is longer than the entering 
edge the ribs being placed somewhat oblique in 
order to secure an even spacing. The wing is 
attached to the frame by two small bamboo 
clips which hold it rigidly and permit easy ad¬ 
justment and is set at an angle of about 4 
degrees with the line of thrust. Both the 


HITTLE WORLD RECORD MODEL 61 



«f ide> 3:lcVa£Lcnt, 


J/ittle Tractor. 


Flan* IfietS 


Jr'oni Flet/alco. 




Diagram 12 






































62 


MODEL AEROPLANES 


floats which take practically the whole weight 
of the machine are situated directly under the 
wing just far enough behind the center of 
gravity to prevent the model from tipping back¬ 
ward. These floats are attached to the engine 
base by means of streamlined bamboo struts. 
Bamboo is also used in the construction of the 
float frames. A single float of triangular sec¬ 
tions is situated just behind the propeller. The 
entire weight of the floats and their attach¬ 
ments is but .23 ounces. 

The propeller which consists of four blades 
is built up of two propellers joined together at 
the hubs and securely glued, the completed pro¬ 
peller having a diameter of 10" with a theoreti¬ 
cal pitch of 14". The blades are fairly nar¬ 
row, tapering almost to a point at the tips. 
The propeller is driven by five strands of %6th" 
strip rubber at about 760 r. p. m. when the 
model is in flight. At the time when the model 
made its record flight of 116 seconds the rubber 
was given 1500 turns which is not the maxi¬ 
mum number of turns. At other times the 


HITTLE WORLD RECORD MODEL 63 


model has flown satisfactorily with less turns 
of the rubber. While in the air the model flies 
very slow and stable notwithstanding its light 
weight and large surface. On three occasions 
the model has made durations of approximately 
90 seconds which rather dispenses the possi¬ 
bility of its being termed a freak. 


THE LA TOUR FLYING BOAT 


One of the most notable results of the Na¬ 
tional Model Aeroplane Competition of 1915 
was the establishing of a new world’s record 
for flying boats. Considering that the model 
flying boat is a difficult type of model to con¬ 
struct and fly, the establishing of this new 
world record of 43 seconds is remarkable. 
Credit for this performance is due Mr. Robert 
La Tour of the Pacific Northwest Model Aero 
Club, who designed, constructed and flew the 
model flying boat which is herewith described 
and illustrated. Diagram 13. 

The frame is made of laminated spruce 40" 
in length, made of two strips glued together. 
They are ^"x^" at the center tapering to 
% 6 " x %" at the ends. The cross braces are of 
split bamboo and are fastened to the frame side 
members by bringing them to a wedge at the 

ends and then inserting them into slots in the 

64 


LA TOUR FLYING BOAT 


65 


sides of the frame side members and are finally 
drilled and bound to the latter. The rear brace 
is of streamlined spruce x*/6"; this butts 
against the frame side members and is bound 
to them. The propeller accommodations are 
made of brass. 

The propellers are 10" in diameter with a 19" 
pitch. These are carved from a block of 
Alaska cedar 1%" wide by £ 4 " thick. Of 
course the propellers may also be made from 
white pine. To turn the propellers 15 strands 
of %” flat rubber are used. 

Bamboo about Vig" square is used to obtain 
the outline of the wings. The main wing has 
a span of 33" with a chord of 5^2". Split bam¬ 
boo is used for the making of the 9 ribs. The 
wing spar or brace is of spruce %6 /r x and is 
fastened below the ribs as illustrated in dia¬ 
gram 13. The elevator is constructed in like 
manner but has a span of only 17" x 4%" and 
has only 5 ribs. A block high is used for 
elevation. Both wings have a camber of 
and are covered on the upper side with silk 


MODEL AEROPLANES 



Diagram 13 



















































































LA TOUR FLYING BOAT 67 

doped with a special varnish and a few coats of 
white shellac. 

The boat is 20" long, 3" in width and shaped 
as shown. The slip is 34 " deep and is located 
7" from the bow. The rear end is brought 
down steeply to avoid the drag of the water on 
this point when the boat is leaving the surface 
of the water. Spruce %4ths of an inch thick is 
used for the making of the sides, but the cross 
bracing is of slightly heavier material, there be¬ 
ing six braces used throughout. The rear 
brace is much heavier in order to withstand the 
pull of the covering and to receive the ends of 
the wire connections. The outriggers or bal¬ 
ancing pontoons are constructed of the same 
material as that of the boat and are held to¬ 
gether by a spruce beam 18" long, y 2 " wide by 
%e" thick, streamlined. This beam is fastened 
to the boat by means of three brads to permit 
changing if necessary. The lower edges of the 
outriggers should clear the water about *4" be¬ 
fore the steps on the boat leave the water. The 
boat and outriggers are covered with silk, 


68 


MODEL AEROPLANES 


shrunk with a special solution and then coated 
several times with white shellac. It is a good 
plan to shellac the interior walls of the boat and 
pontoons before covering to prevent them from 
losing their form by becoming soft from the 
influence of water in the case of a puncture. 

The boat is connected to the frame at its 
front by two steel wires, their ends being in¬ 
serted into the cross members of the boat, and 
then brought up along the sides, crossed and 
then bound to the frame. A similar pair of 
connecting wires are used to connect the rear 
end of the boat to the rear end of the frame. 
A U-shaped wire is bound to the outrigger 
beam and frame. A single diagonal strip of 
bamboo is also fastened to the outrigger beam 
with a brad, its upper end being bound to the 
cross bracing of the frame, making a very solid 
connection. 

Under ideal weather conditions this model 
will fly on 12 strands of rubber with the possi¬ 
bility of a better duration than has been made. 
But, however, with 15 strands the model will 


LA TOUR FLYING BOAT 


69 


rise at every attempt. More rubber, however, 
causes the bow of the boat to nose under and to 
accommodate this increase of power the boat 
should be lengthened. 


THE COOK NO. 42 WORLD 
RECORD MODEL 


(twin propeller hydroaeroplane, 100.6 

SECONDS RISING FROM WATER) 

During the National Model Aeroplane Com¬ 
petition of 1915 held under the auspices of the 
Aero Club of America, a number of new world 
records were established, one of which was for 
twin propeller hydroaeroplanes. The credit 
for this record is due Mr. Ellis C. Cook of the 
Illinois Model Aero Club, who succeeded in 
getting his model hydroaeroplane—which by 
the way is a rather difficult type of model to 
operate—to rise from the water and remain in 
the air for a duration of 100.6 seconds. This 
model is of the common A frame design with 
the floats or pontoons arranged in the familiar 
fashion, two forward and one aft. The model 

is fairly light, weighing, when complete, 3.33 

70 



THE COOK NO. 42 MODEL 71 

ounces, ounce of which is made up in rubber 
strands for motive power. Diagram 14. 

The frame is made of two sticks of white 
pine for side members, each member measuring 
38%" in length, Vis" in depth, by Vs" in width. 
These are cut to taper toward the ends where 
they are only Vs" in width by Vis" in depth in the 
front and rear respectively. Three “X” strips 
of streamlined bamboo measuring Vis" in width 
by % 4 ths of an inch in depth, are used for brac¬ 
ing the frame between the front and rear and 
are arranged as shown in diagram 14. The 
propeller bearings are of small streamlined 
forgings of light weight, and are bound to the 
rear end of each side member first by gluing, 
then binding around with thread. The front 
hook is made of No. 16 piano wire and is bound 
to the frame as shown in diagram 14. The 
chassis which holds the floats or pontoons is 
made of %z" bamboo bent to shape and bound 
to the frame members. By the use of rubber 
strands the floats are attached to the chassis; 


72 


MODEL AEROPLANES 


the forward ones being attached so that angle 
may be adjusted. 

The main wing has a span of 36" and a 
chord of 5" and is constructed of two white 
pine beams each 39" long, with bamboo wing 
tips. The ribs, seven in number, are also made 
of bamboo and are spaced along the edges of 
the wing at a distance of 4 Yz" apart. The 
“elevator” or front wing has a span of 14" and 
a chord of > th e framework of which is 
made entirely of bamboo. The entering edge 
of this wing is given a slightly greater dihedral 
so that the angle of incidence at the tips is 
greater than at the center. By this method the 
added incidence in the front wing is obtained. 
By the use of rubber bands both wings are at¬ 
tached to the frame. 

The two forward floats are spaced eight in¬ 
ches apart and are of the stepped type, the step 
being 3*4" from the front and has a depth 
of These two floats are separated by 

two bamboo strips as shown in the diagram, 


THE COOK NO. 42 MODEL 


73 



Diagram 14 


























































74 


MODEL AEROPLANES 


which are tied to the rounded portion of 
the under carriage by small rubber bands. By 
the sliding of these strips back and forth the 
necessary angle of the floats may be obtained to 
suit conditions. The floats are built up with 
two thin pieces of white pine for sides, sepa¬ 
rated by small pieces of wood about one-half 
the size of a match in cross section. Chiffon 
veiling which is used for the covering of the 
wings, is also used for the covering of the 
floats, after which it is covered with a special 
preparation to render both the wings and the 
floats air and water-tight. 

The two ten-inch propellers with which the 
model is fitted have a theoretical pitch of twelve 
and one-half inches. The propellers are 
carved from blanks one-half inch thick, the 
blades of the completed propellers having a 
maximum width of one inch at a radius of 
three inches. The propeller shafts are made 
from No. 16 piano wire and have small wash¬ 
ers for bearings. Each propeller is driven by 
three strands of J /%” strip elastic. The rub- 


THE COOK NO. 42 MODEL 


75 


ber is given 1700 to 1750 turns and revolves the 
propellers at 1150-1200 r. p. m., when the 
model is in flight. 

The model usually runs over the surface of 
the water for a distance of from two to three 
feet before it rises, after which it climbs at a 
very steep angle to the necessary altitude. 
The model seems, when in flight, to be slightly 
overpowered but this is misleading. The rub¬ 
bers usually unwind in from 85 to 90 seconds. 
On four out of six flights this model has made 
a duration of between 98 and 100 seconds 
which is rather unusual for a model of this 
type. 


THE RUDY FUNK DURATION 

MODEL 


Of the many different types of duration 
models that have made their appearance dur¬ 
ing the year of 1915 perhaps the model de¬ 
scribed herewith, constructed and flown by 
Mr. Rudolph Funk, of the Aero Science Club, 
was one of the most successful. Unlike most 
models the propellers of this model are bent 
and not cut. This model made its appearance 
during the latter part of 1915, on several oc¬ 
casions having flown for over 100 seconds dur¬ 
ation. Diagram 15. 

While retaining the important characteristics 
of his standard model, slight changes have been 
made. Instead of the usual wire for the con¬ 
struction of the frame of the wings, bamboo is 
used in its place for lightness and strength. 

The wing frames are single surfaced, China 

76 


RUDY FUNK MODEL 


77 


silk being used for covering. The “dope” 
which is used to render the silk airtight is made 
by dissolving celluloid in banana oil. This in 
turn is applied to the silk with a soft brush. 

The camber of the main wing is at 
the center, with a slight reduction towards 
the negative tips; it also has a dihedral angle 
of 2 degrees. The main beam, which is secured 
to the under side of the frame for rigidness, is 
of spruce i" by 5-64”, tapering to Y\ f x 5-64”. 
The ribs for the main wing and small wing or 
“elevator” are cut from solid pieces of bamboo 
3-16” thick by *4" wide. These pieces of bam¬ 
boo are first bent to the proper camber and are 
then cut into strips each 1-16" wide. The ribs 
are next tapered to a V at the bottom, toward 
the trailing edge, as shown in diagram 15, and 
also toward the entering edge. To accommo¬ 
date the entering and trailing edges of the 
frame, each rib is slit slightly at both ends. 
Both edges of the frame are then inserted in the 
slots at the ends of the ribs and bound around 
with silk thread. 


78 


MODEL AEROPLANES 



Diagram 15 







































RUDY FUNK MODEL 


79 


The frame is composed of two sticks of silver 
spruce 38" in length, 5-16" x 3-16", tapering to 
x 5-32", held apart by a streamline bamboo 
cross brace in the center. An additional brace 
of bamboo is securely fastened across the frame 
toward the front. The propeller brace con¬ 
sists of a streamline-cut piece of bamboo 125/2" 
in length by y " in width at the center, tapering 
to yy r toward the ends. The propeller brace 
is inserted in slots cut in the rear ends of the 
frame members, then bound and glued. 

The propellers are bent from birch veneer, 
the bending being done over an alcohol flame 
as illustrated in diagram 15. But first of all 
the blades are cut to shape, sandpapered and 
finished before they are bent. As shown in the 
drawing a slot is filed in the hub of each blade 
to enable the propeller shaft to pass through 
when both have been glued together. The 
blades are then glued and bound together, first 
by placing a piece of wire in the slots to insure 
their being centered and also to prevent their 
being filled with glue. After this has been done 


8o 


MODEL AEROPLANES 


each propeller is given three coats of the same 
dope as is used on the wings. 

The propeller bearings are turned out of 
1-32" bronze tubing, the length of each bearing 
being J 4 ". Steel washers are slipped over 
the propeller shaft, between the bearing and 
propeller to insure smooth running. The pro¬ 
peller shafts are made from steel hatpins which 
are heated at both ends, one end of which is 

bent into a loop to receive the rubber strands, 

. * » 

the other end being bent around the hub of the 
propeller to prevent the shaft from slipping 
during the unwinding of the rubbers. Two 
strips of brass, each x 2 "> are bent around 
the one-half inch bearing and soldered. The 
brass strips are then glued and bound onto the 
ends of the propeller brace as shown in diagram 
15 * 





■tm * '4 




Rudy Funk speed model 



Schober compressed air driven monoplane. McMahon 
compressed air driven tractor (right) 

















THE ALSON H. WHEELER WORLD 
RECORD MODEL 

(TWIN PUSHER BIPLANE 143 SEC. DURATION 
RISING FROM THE GROUND) 

Since the beginning of model flying very 
little attention has been paid to the model bi¬ 
plane. Practically all records are held by 
model aeroplanes of the monoplane type. 
With this fact in view, the record established 
by Mr. Wheeler with his Twin Pusher Biplane 
is extraordinary, in so far as it surpasses many 
of the monoplane records. This model is a 
very slow flyer, and has excellent gliding abil¬ 
ity. At the time when this model flew and 
broke the world's record, the greater portion of 
the flight consisted of a beautiful glide of 86 
seconds’ duration, after the power gave out, 
making it possible for the model to remain in 

the air for a duration of 143 seconds. 

81 


82 


MODEL AEROPLANES 


The frame consists of two I-beams, each 
48" in length, running parallel, and spaced by 
cross pieces, each piece Iij 4 " long. The 
bearing blocks used made it possible for the 
propellers to clear by one-half inch. Two 12" 
expanding pitch racing propellers are used 
and these are mounted on ball bearing shafts. 
The main upper plane has a span of 34" with 
a chord of 5", the lower plane being 26" by 5". 
The elevator consists of two planes, each meas¬ 
uring 14" by 5". Cork wheels are used, each 
being one inch in diameter. For motive power 
one-eighth inch flat rubber is used, this being 
coated with glycerine to prevent sticking. 



Alson H. Wheeler twin pusher Biplane 



C. V. Obst tractor model 


0 











A MODEL WARPLANE 


The model shown in the accompanying 
photograph was constructed by Master R. 
O’Neill, of Montreal, Canada. The machine 
was designed after one of the leading war¬ 
planes now in active service abroad and in 
carrying out the entire features he did not fail 
to include the identification marks which are 
of utmost importance in the war zone. 

The dimensions of the model are as follows: 
Length of fuselage, 23"; span of top wing, 
33"; span of lower wing, 29", both having a 
chord of 7". Motive power is derived from 
two % inch square elastic strands which ope¬ 
rate a multiple gear to which is attached a 
ten" propeller. 

In coloring the model a dull aluminum was 

selected. Complete the model weighs 12 

ounces. Perhaps the most interesting feature 

83 


8 4 


MODEL AEROPLANES 


of the model is the ability to change it to a 
monoplane by the removal of the upper wing 
after which the lower wing is raised to the 
sockets in the fuselage which were especially 
arranged for that particular purpose. 


vS 



Model warplane 















* 










* 











A SIMPLE COMPRESSED AIR ENGINE 

During the past few years model flyers in 
America have shown a tendency toward the 
adoption of compressed air engines for use in 
connection with model aeroplanes. Hitherto, 
England has been the home of the compressed 
air engine, where a great deal of experimenting 
has been carried on, to a considerable degree 
of success. Flights of over 40 seconds have 
been made with models in which compressed 
air power plants were used. But, however, the 
desire on the part of a large majority of model 
flyers in America to build scientific models, that 
is, models more closely resembling large ma¬ 
chines, has made it necessary to find a more 
suitable means of propulsion; rubber strands 
being unsatisfactory for such purposes. Many 
different types of compressed air engines have 
made their appearance during the past few 
years, among which the two cylinder opposed 

85 


86 


MODEL AEROPLANES 


type is very favorably looked upon, because it 
is perhaps one of the easiest to construct. 

To make a simple two cylinder opposed com¬ 
pressed air power plant, as illustrated in Figure 
i of diagram 16, it is not necessary that the 
builder be in possession of a machine shop. A 
file, drill, small gas blow torch and a small vise 
comprise the principal tools for the making of 
the engine. 

The first things needed in the making of this 
engine are cylinders. For the making of the 
cylinders two fishing rod ferrules, known as 
female ferrules, are required. And for the 
heads of the cylinders, two male ferrules are 
required. Such ferrules can be secured at 
most any sporting goods store. The female 
ferrules should be filed down to a length of 
2", cut down on one side a distance of 
of the diameter, then cut in from the end as 
shown in Figure 7. When this has been done 
the two male ferrules should be cut off a dis¬ 
tance of from the top as shown in Figure 
7a, to serve as heads for the cylinders. A hole 


SIMPLE COMPRESSED AIR ENGINE 87 



Diagram 16 















































































































88 


MODEL AEROPLANES 


Ys" in diameter should be drilled in the center 
of each head so as to enable the connecting of 
the intake pipes. By the use of soft wire solder 
the heads should be soldered into the ends of the 
cylinders as shown in Figure id. 

The pistons should now be made; for this pur¬ 
pose two additional male ferrules are required. 
These should be made to operate freely within 
the cylinders by twisting them in a rag which 
has been saturated with oil and upon which has 
been shaken fine powdered emery. When they 
have been made to operate freely they should 
be cut down one-half inch from the closed end 
as shown in Figure 5a. For the connecting 
rods, 2 pieces of brass tubing, each in 
diameter by i%" long, are required, and, as 
illustrated in Figure 6, should be flattened out 
at either end and through each end a hole 3-32" 
in diameter should be drilled. For the con¬ 
necting of the piston rods to the pistons, studs 
are required, and these should be cut from a 
piece of brass rod yy r in diameter by ^4" 
in length. As two studs are necessary, one 


SIMPLE COMPRESSED AIR ENGINE 89 

for each piston, this piece should be cut in 
half, after which each piece should be filed in 
at one end deep enough to receive the end of 
the connecting rod. Before soldering the 
studs to the heads of the pistons, however, 
the connecting rods should be joined to the 
studs by the use of a steel pin which is passed 
through the stud and connecting rod, after 
which the ends of the pin are flattened, to keep 
it in position as shown in Figure 5a. 

For the outside valve mechanism and also to 
serve in the capacity as a bearing for the crank¬ 
shaft, a piece of brass tubing *4" in diameter 
by 1 Yz" long is required. Into this should be 
drilled three holes, each j/g" in diameter, and 
each apart as shown in Figure 4. Next, 
for the valve shaft and also propeller accommo¬ 
dation, secure a piece of 3-16" drill rod 2" long. 
On the left hand side of the valve shaft, as 
shown in Figure 3, a cut 1-32" deep by J 4 " in 
length is made 1" from the end. Another cut 
of the. same dimensions is made on the right 
side only; this cut is made at a distance of 
from the stud end. 


90 


MODEL AEROPLANES 


As shown in Figure if, the crank throw con¬ 
sists of a flat piece of steel, 3-32" thick, in 
length by in width. At each end of the 
crank throw a hole 3-16" in diameter should be 
drilled, the holes to be one-half inch apart. 
Into one hole a piece of steel drill rod 3-32" in 
diameter by ]/y r long is soldered, to which the 
connecting rods are mounted, as shown in Fig¬ 
ure if. Into the other hole the stud end of the 
crank throw is soldered. 

Before making the tank it is most desirable 
to assemble the parts of the engine, and this 
may be done by first fitting the pistons into the 
cylinders as shown in Figure i-b, after which 
the cylinders should be lapped one over the 
other and soldered as shown in Figure i-a. 
When this has been done a hole one-fourth of 
an inch in diameter should be drilled half way 
between the ends of the cylinders, and into 
this hole should be soldered one end of the valve 
casing shown in Figure 4. For the inlet pipes 
as shown in Figure i-c secure two pieces of 
yy f brass tubing and after heating until soft, 



Schober pusher type compressed air driven monoplane 



& 


Schober compressed air driven biplane 

















SIMPLE COMPRESSED AIR ENGINE 91 


bend both to a shape similar to that shown in 
Figure i-c. When this has been done solder 
one end to the end of the cylinder and the other 
in the second hole of the valve shaft casing. 
The valve shaft should now be inserted in the 
valve shaft casing and the connecting rods 
sprung onto the crank throw as shown in Fig¬ 
ure i-d. To loosen up the parts of the engine 
which have just been assembled it should be 
filled with oil and by tightly holding the crank¬ 
shaft in the jaws of a drill the engine can be 
worked for a few minutes. 

The tank is made from a sheet of brass or 
copper foil 15" long by 1-1000" thick. This 
is made in the form of a cylinder, the edges 
of which are soldered together as shown in 
Figure 2. Sometimes this seam is riveted 
every one-half inch to increase its strength, 
but in most cases solder is all that is required 
to hold the edges together. For the caps, or 
ends, the tops of two small oil cans are used, 
each can measuring 2 * 4 " in diameter. To 
complete the caps two discs of metal should be 


92 


MODEL AEROPLANES 


soldered over the ends of the cans where for¬ 
merly the spouts were inserted, the bottoms of 
the cans having been removed. The bottom 
edges of the cans should be soldered to the 
ends of the tank as shown in Figure 2. Into 
one end of the completed tank a hole large 
enough to receive an ordinary bicycle air valve 
should be drilled. Figure 2. Another hole is 
drilled into the other end of the tank, into which 
is soldered a small gas cock to act as a valve. 
Figure 2. This should be filed down where 
necessary, to eliminate unnecessary weight. 
To connect the tank with the engine, a piece of 
brass tubing 3" long is required, the ends 
of which are soldered into the holes in the valve 
shaft casing nearest the cylinders, as shown in 
Figure 1 ee. As shown in Figure 1 ee, a hole 
yy f in diameter is drilled in one side of this 
piece, but not through, in the end nearest the 
tank. Another piece of brass tubing yy f in 
diameter is required to connect the tank with 
the engine, one end of which is soldered to the 
cock in the tank, the other in the hole in the 


SIMPLE COMPRESSED AIR ENGINE 93 

pipe which leads from the engine to the tank, 
illustrated in Figure 1 ee, thus completing the 
engine. 

In conclusion it is suggested that the builder 
exercise careful judgment in both the making 
and assembling of the different parts of the 
engine in order to avoid unnecessary trouble 
and secure satisfactory results. After having 
constructed an engine as has just been de¬ 
scribed, the constructor may find it to his desire 
to construct a different type of engine for ex¬ 
perimental purposes. The constructor there¬ 
fore may find the descriptions of satisfactory 
compressed air engines in the following para¬ 
graphs of suggestive value. 


COMPRESSED AIR DRIVEN MODEL 


The development of the compressed air en¬ 
gine has given an added impetus to model mak¬ 
ing, necessitating more scientific experiment¬ 
ing and developing the art of model flying 
along lines of greater value to those who may 
eventually take up the work of building our 
future air fleets. 

In the accompanying illustration is shown 
a model aeroplane of monoplane type driven 
by a three-cylinder rotary engine which was 
constructed by Edward Willard Dart of South 
Norwalk, Connecticut. 

The engine was constructed after several 
months of patient labor. Careful judgment 
was exercised in the drafting of the plane and 
likewise in the assembling of the engine for 
it is absolutely essential that all parts be prop¬ 
erly fitted as to enable the engine to run 

94 


A 



Model by Edward Willard Dart 






COMPRESSED AIR DRIVEN MODEL 95 


smoothly. In designing the wings every de¬ 
tail was taken into consideration to insure 
good flying. 

The main wing has a spread of 58" and 7" 
in chord. The elevator measures 23" in 
spread and 6" in chord. In the construction 
of both wings bamboo ribs are used, the 
frames being covered over with China silk and 
coated with celluloid solution. The main 
wing is made in two sections to facilitate quick 
adjustment to the fuselage. 


COMPRESSED AIR MODELS 


THE MC MAHON COMPRESSED AIR DRIVEN 

MONOPLANE 

One of the latest developments in the field 
of model flying is the McMahon compressed air 
driven monoplane. This model was built to 
be used as either a tractor or pusher, but in view 
of its ability to balance more easily as a pusher 
most of the experiments have been carried out 
on this machine as a pusher. The machine in 
itself is simple and inexpensive to construct, the 
chief portion of the expense being involved in 
the making of the engine. By using the ma¬ 
chine as a pusher a great deal of protection is 
afforded both the propeller and engine, and this 
protection helps to avoid damaging the pro¬ 
peller or engine, which would mean an addi¬ 
tional expenditure for repairs, thus minimizing 
the cost of flying the model. 


9 6 


COMPRESSED AIR MODELS 


97 

The frame has been made to accommodate 
both the tank and engine, and this is done by 
using two 30" strips of spruce, each l /y' wide 
by deep, laid side by side, a distance of 
three inches apart, up to within 10" of the 
front, as shown in the accompanying photo¬ 
graph. No braces are used on the frame, as 
the tank, when securely fastened between the 
frame, acts in that capacity. 

The wings are made in two sections, each 
section measuring 24" in span by 8" in chord, 
consisting of two main spars, 3-16" in diameter, 
one for the entering edge and one for the trail¬ 
ing edge. To these edges, at a distance of 
three inches apart, are attached bamboo ribs, 
18 in all, each measuring 8" in length by *4" 
in width by 1-16" thick. The wings are round 
at the tips, and have a camber of approximately 
one-half inch, but they are not set at an angle 
of incidence. Light China silk is used for 
covering and after being glued over the top of 
the wing frame is given two coats of dope to 
shrink and fill the pores of the fabric. A good 


9 8 


MODEL AEROPLANES 


“dope” for the purpose can be made from cel¬ 
luloid dissolved in banana oil. The wing sec¬ 
tions are attached to the frame and braced by 
light wire. The forward wing or “elevator” is 
made in the same manner as the main wing, but 
should measure only i8 // x 3". Instead of be¬ 
ing made in two sections as the main wing, the 
forward wing is made in one piece. 

The chassis is made by forming two V struts 
from strong steel wire sufficiently large enough 
so that when they are attached to the frame of 
the model the forward part will be 9" above the 
ground. One V strut is securely fastened to 
either side of the frame, at a distance of 8" 
from the front. A 7" axle is fastened to the 
ends of these struts. On the axle are mounted 
two light wheels, each about 2" in diameter. 
The chassis is braced by light piano wire. 

The rear skid is made in the same manner as 
the forward skid, only that the ends of the 
struts are brought together and a wheel 1 inch 
in diameter is mounted at the bottom ends by 
means of a short axle. The struts are not 



John McMahon and his compressed air driven 

monoplane 



Frank Schober preparing his model for flight 
Gauge to determine pressure of air may be 
seen in photograph 
















COMPRESSED AIR MODELS 


99 


more than 7^/2" long, thus allowing a slight 
angle to the machine when it is resting upon 
the ground. 

The machine complete does not weigh over 
7 ounces. The power plant used in connection 
with this model is of the two cylinder opposed 
engine type, with tank such as has just been 
described in the foregoing chapter. 

The tank is mounted in the frame by drilling 
a 1-16" hole through either end of the tank, 
through which a drill rod of this diameter can 
be inserted. About JLjths of the drill rod 
should extend out on each side of the tank, to 
permit the fastening of the tank to the frame 
side members. This method of mounting the 
tank serves two purposes to a satisfactory de¬ 
gree. First, it permits secure fastening; sec¬ 
ond, as the rods are passed through the side and 
cap of the tank they help materially in prevent¬ 
ing the caps from being blown off in the event 
of excessive pressure. 


o 



) > 


) 


The McMahon Compressed Air Driven 

Biplane 

In the McMahon model we find a very satis¬ 
factory type of compressed air driven model. 
On several occasions this model has made 
flights of over 200 feet with a duration of be¬ 
tween 10 and 15 seconds, and the indications 
are that by the use of a more powerful engine 
the model can be made to fly a greater distance, 
with a corresponding increase of duration. 
The engine used in connection with the model 
is of the two cylinder opposed type, such as 
described in the foregoing paragraphs. The 
tank, however, is somewhat different in design 
from that just described, it having been made 
of 28 gauge sheet bronze, riveted every one- 
half inch. The two long bolts that hold the 
steel caps on either end of the tank also serve as 
attachments for the spars that hold the tank to 
the engine bed, as shown in diagram 18. The 
tank has been satisfactorily charged to a pres- 

100 



C V ( 


COMPRESSED AIR MODELS ioi 

sure of 200 lbs. per square inch, but only a pres¬ 
sure of 150 lbs. is necessary to operate the 
engine. The tank measures 10" in length by 
3" in diameter and weighs 7 ounces.' 

The wings of this machine are single sur¬ 
faced and covered with fiber paper. The top 
wing measures 42" in span by 6" in chord. 
The lower wing is 24" by 6". The wings have 
a total surface of 396 square inches and are 
built up of two 3-16" dowel sticks, flattened to 
streamline shape. Only two sets of uprights 
separate the wings, thus adding to the stream¬ 
line appearance of the machine. 

Both tail and rudder are double surfaced and 
are built entirely of bamboo for lightness, 
the tail being made in the form of a half cir¬ 
cle measuring 12" by 8". Steel wire is used 
on the construction of the landing chassis, the 
chassis being so designed as to render it capable 
of withstanding the most violent shock that it 
may possibly receive in landing. The propeller 
used in connection with the model is 14" in di¬ 
ameter and has an approximate pitch of 18". 


102 


MODEL AEROPLANES 


//^//[ahon, piplane . 
Ccmprctefxb CLir JDrtifen .. 


Plan. 



meiof 


Pbh/er Plant. 


JtflcPCei'hiconj . 



Diagram 17 























































































COMPRESSED AIR ENGINES 

THE WISE COMPRESSED AIR ENGINE 

Although of peculiar construction, the 
Wise rotary compressed air engine offers a 
very interesting design from a viewpoint of in¬ 
genuity. This engine embodies a number of 
novel features not hitherto employed in the con¬ 
struction of compressed air engines, and in 
view of the fact that the majority of com¬ 
pressed air engines are made on the principle of 
the opposed type, this engine suggests many 
possibilities for the rotary type engine. 

The engine consists of five cylinders and 
weighs four ounces, including the propeller and 
mounting frame. On a pressure of 15 lbs. the 
engine will revolve at a speed of 1000 r.p.m. 
The connecting rods are fastened to the crank¬ 
shaft by means of segments and are held by 

two rings, making it possible to remove any one 

103 


104 


MODEL AEROPLANES 


piston without disturbing the others. This is 
done by simply removing a nut and one ring. 
The crank case is made from seamless brass 
tubing, into which the cylinders are brazed. 
The valve cage and cylinder heads are also 
turned separately and brazed. One ring only 
is used in connection with the pistons. The 
cylinders have a bore of 11-32", with a piston 
stroke of 7-16". In view of the fact that pull 
rods show a greater tendency to overcome cen¬ 
trifugal force, they are used instead of push 
rods to operate the valves. The crankshaft has 
but one post, which is uncovered in turn by each 
inlet pipe as the engine revolves. The “over¬ 
hang” method is used to mount this engine to 
the model. With the exception of the valve 
springs, the entire engine, including the mount¬ 
ing frame and tank, is made of brass. 

The Schober-Funk Compressed Air Engine 

Two of the most enthusiastic advocates of 
the compressed air engine for use in model aero¬ 
planes are Messrs. Frank Schober and Rudolph 



Schober-Funk five cylinder rotary engine 













COMPRESSED AIR ENGINES 105 

Funk, both members of the Aero Science Club. 
For a number of months both these gentlemen 
have experimented with compressed air engines 
of various designs, until they finally produced 
what is perhaps one of the most satisfactory 
rotary engines now in use, from a standpoint 
of simplicity and results. 

As can be seen from the accompanying illus¬ 
tration, this little engine is remarkably sim¬ 
ple in appearance. The engine complete, with 
equipment, weighs at the most but 14 ounces. 
The cylinders, three in all, are stamped from 
brass shells for strength and lightness. The 
pistons are made from ebony fiber. The cylin¬ 
ders have a bore of y§", with a piston stroke 
of J 4 ". The crank case is built up from 
a small piece of brass tubing and is drilled 
out for lightness. The crankshaft is hollow, 
and is supported at the rear by a special bear¬ 
ing which acts as a rotary valve, admitting the 
intake through the crankshaft and permitting 
the exhaust to escape through a specially con¬ 
structed bearing. 


106 MODEL AEROPLANES 

The tank is constructed of 30 gauge sheet 
bronze, wire wound, and fitted at the ends with 
spun brass caps. The actual weight of the 
engine alone is 2^ ounces, the tank and fittings 
weighing n 1 /* ounces, making the total weight 
of the complete power plant 14 ounces. 

THE SCHOBER FOUR CYLINDER OPPOSED 

ENGINE 

Another interesting type of compressed air 
engine that has been developed in America is 
the Schober four cylinder opposed engine. 
While this engine is different in appearance 
from most compressed air engines, it has been 
made to work satisfactorily and is consistent 
with the same high class construction that is 
displayed in most all of Mr. Schober’s engines. 
The accompanying diagram 17 illustrates the 
method of operation of the four cylinder engine. 

The crank case is constructed from four 
pieces of 24 gauge spring brass, substantially 
connected in the form of a rectangle, the top 
and bottom being left open. The front and 


COMPRESSED AIR ENGINES 107 



Diagram 18 





































































































































































MODEL AEROPLANES 


,io8 

rear walls have flanges which engage the inside 
of the side walls and are secured thereto by 
four small screws on each side, thereby making 
it an easy matter to take the crank case apart. 

The four cylinders are made from drawn 
brass shells and have a bore of and stroke 
of J 4 ". The pistons are made of solid 
red fiber. The two-throw crank-shaft is 
built up of steel with brass webs. The 
bearings are of steel. The valves, being over¬ 
head, are driven by a gear mounted at the end 
of the crankshaft, the gear driving the valve 
shaft by means of a gear on that shaft, with 
which the crankshaft gear meshes. The valve 
arrangement, as shown in diagram 18, consists 
of four recesses cut into the valve shaft, two 
of which allow the air to pass from the inlet 
pipes, which lead into the valve chamber at the 
center of same, to two of the cylinders at once, 
while the other two recesses allow the exhaust 
to pass from openings in the sides of the valve 
chamber. 

The cylinders are secured to the side plates 



The interesting horizontal-opposed Jopson gasoline engine 
for model aeroplanes. The top photograph shows the 
half-speed shaft and the arrangement of the valve mecha¬ 
nism. This engine is air cooled, develops i h.p. at 1,500 
r.p.m., and weighs 7V2 lbs., including gasoline tank and 
propeller. The bottom view shows the engine with pro¬ 
peller in situ. Courtesy Flight. 













COMPRESSED AIR ENGINES 109 


of the crank case so that when those side plates 
are removed, the cylinders are removed with 
them. The pipes are detachable at their cen¬ 
ters; small pipes running to the heads of the 
cylinders extending into the larger pipes which 
run to the valve chamber. This arrangement 
is shown in the end view of the engine. A 17" 
propeller is used in connection with this engine. 


GASOLINE ENGINES 


THE JOPSON I H. P. GASOLINE ENGINE 
FOR MODEL AEROPLANES 

During the past few years several attempts 
have been made, both in this country and 
abroad, to produce a reliable gasoline engine for 
model aeroplane work, but mostly without any 
degree of success. The reason for this inabil¬ 
ity, no doubt, is due to the scarcity of small 
working parts sufficiently light and at the same 
time reliable. The engine described herewith, 
designed by Mr. W. G. Jopson, a member of the 
Manchester Aero Club, England, is one of the 
few that have been made to work satisfactorily. 

As the accompanying diagrams 19 and 20 
and photograph show, the engine is of the four¬ 
cycle, horizontal opposed type, having two cast- 
iron cylinders of i}4" bore and 1 stroke. 

Each cylinder is cast in one piece, and as the 

no 


GASOLINE ENGINES 


hi 


engine is air cooled, they are cast with radiat¬ 
ing fins. One h.p. is developed at 1500 r.p.m. 
The total weight of the engine, gasoline tank 
and propeller is 7^ lbs. In preparing the de¬ 
sign of this engine, the designs of similar full- 
sized aero engines were followed as far as pos¬ 
sible. The pistons are similar to those used 
on large aero engines and are fitted with two 
rings; the crankshaft is turned out of two inch 
special bar steel, and is carried in two phos¬ 
phor-bronze bearings. There is no special 
feature about the connecting rods, these being 
of the standard type, but very strong and light. 
To enable the two cylinders to be exactly op¬ 
posite one another, the connecting-rods are off¬ 
set in the pistons and are connected to the lat¬ 
ter by gudgeonpins. The aluminum crank¬ 
case is extremely simple, being cylindrical and 
vertically divided. The inlet valves are auto¬ 
matic, the exhaust valves being mechanically 
operated; the cam-shaft is driven from the 
main shaft by two-to-one gearing. To assist 
the exhaust, and also the cooling, small holes 


,112 


MODEL AEROPLANES 



Diagram 19 

Sectional elevation of the 1 h. p. Jopson gasoline engine for 
models. The disposition of the gasoline tank and wick 
carburettor is particularly noteworthy. It will be seen 
that metal journals are provided for the crank-shaft, 
which is turned out of 2-inch bar steel. Courtesy Flight. 





































GASOLINE ENGINES 


113 

are drilled round the cylinder in such a position 
that when the piston is at the inner end of its 
stroke, these holes are uncovered, thus permit¬ 
ting the hot exhaust to escape, and so relieve 
the amount passing through the exhaust valves. 
The commutator is also driven off the cam¬ 
shaft, as shown in the drawing. No distribu¬ 
tor is fitted to the commutator, as small ones 
are somewhat troublesome and very light coils 
are obtainable at a reasonable price. 

The gasoline tank is made of copper in 
stream-line form, and is usually fitted to the 
back of the crankcase, thus reducing the head 
resistance, but if desired it can be fitted in any 
other position. The action of the carburetor 
can be easily seen from the drawings; it is of 
the surface type and much simpler, lighter and 
quite as efficient as the spray type. Specially 
light and simple spark plugs are used, that 
give very little trouble. The propeller used in 
connection with this engine is somewhat out of 
the ordinary, having been specially designed 
for this engine, and patented. The propeller 


11 4 MODEL AEROPLANES 

is made entirely of aluminum and has a varia¬ 
ble pitch, this being easily obtainable, as the 
blades are graduated so that any desired pitch, 
within certain limits, may be given at once. 
The results of a series of tests on a 30 inch pro¬ 
peller are shown on the accompanying chart, 
and from it the thrust as certain speeds with a 
certain pitch can be obtained. Taking the en¬ 
gine running at 1540 r.p.m. with a pitch of 15", 
the thrust comes out at 9^4 lbs., or more than 
the weight of the engine and accessories. 


GASOLINE ENGINES 


“5 



Diagram 20 

Diagram of results obtained from tests of the 1 h.p. Jopson 
model gasoline engine, showing the thrust in pounds at 
varying speeds with propellers of different pitch. Cour¬ 
tesy Flight 


































THE MIDGET AERO GASOLINE 

ENGINE 


Although numerous model constructors in 
America are experimenting with model gaso¬ 
line engines, the Midget Gasoline Engine, the 
product of the Aero Engine Company, Boston, 
Massachusetts, is perhaps the most satisfac¬ 
tory up to the present time. An engine of this 
type was used by Mr. P. C. McCutchen of 
Philadelphia, Pennsylvania, in his 8 foot Voi- 
sin Type Bi-plane Model, for which he claims 
a number of satisfactory flights. 

The engine is made from the best iron, steel, 
aluminum and bronze and the complete weight 
including a special carburetor, spark plug and 
spark coil is 2^2 lbs. From the top of the cyl¬ 
inder head to the bottom of the crank case the 
engine measures 7". It is possible to obtain 
from this engine various speeds from 400 to 



The Midget pz H. P. gasoline engine 


. 









MIDGET AERO GASOLINE MOTOR ny 

2/00 r.p.m., at which speed it develops *4 h.p. 
The propeller used in connection with this 
engine measures 18" in diameter and has a 
13" pitch. 

It might be of interest to know that one of 
the parties responsible for the development of 
this engine is Mr. H. W. Aitken, a former 
model maker and who is now connected with 
one of the largest aero engine manufacturing 
companies in America. 


STEAM POWER PLANTS 

Aside from the compressed air engine there 
is the steam driven engine which has been used 
abroad to considerable degree of success. 
Owing to the difficulty in constructing and 
operating a steam driven engine, very few 
model flyers in America have devoted any at¬ 
tention to the development of this engine as a 
means of propulsion for model aeroplanes. 
But irrespective of the limitations of the steam 
engine a great deal of experimentation has been 
carried on in England, and without doubt it will 
soon be experimented with in America. Per¬ 
haps one of the most successful steam power 
plants to have been designed since the develop¬ 
ment of the Langley steam driven model, is the 
Groves type of steam power plant, designed by 
Mr. H. H. Groves, of England. On one occa¬ 
sion several flights were made with a model 

118 


STEAM POWER PLANTS 119 

driven by a small steam engine of the Groves 
type weighing 3 lbs. The model proved itself 
capable of rising from the ground under its 
own power and when launched it flew a distance 
of 450 feet. This is not a long flight when 
compared with the flight made by Prof. Lang¬ 
ley’s steam driven model on November 28, 
1896, of three-quarters of a mile in 1 minute 
and 45 seconds, but the size of the models and 
also that Mr. Groves’ model only made a dura¬ 
tion of 30 seconds, must be considered. The 
model was loaded 12 ounces to the square foot 
and had a soaring velocity of some 20 m.p.h. 
The total weight of the power plant was 
lbs. Propeller thrust 10 to 12 ounces. The 
total weight of the model was 48 ounces. The 
type of steam plant used in connection with this 
model was of the flash boiler, pressure fed type, 
with benzoline for fuel. 

Mr. Groves has done considerable experi¬ 
menting with the steam driven type power 
plant. Many of the designs used in the con¬ 
struction of steam plants for models are taken 


120 


MODEL AEROPLANES 


from his designs. A Groves steam power 
plant is employed in one of Mr. V. E. Johnson’s 
(Model Editor of Flight ) model hydroaero¬ 
planes, the first power-driven, or “mechanically 
driven” model hydroaeroplane (so far as can 
be learned) to rise from the surface of the 
water under its own power. This model has a 
total weight of 3 lbs. 4 ounces. 

Another advocafe of the steam driven type 
model is Mr. G. Harris, also of England. Sev¬ 
eral good flights were made by Mr. Harris 
with his pusher type monoplane equipped with 
a steam driven engine. As a result of his ex¬ 
periments he concluded that mushroom valves 
with a lift of 1-64 part of an inch were best, 
used in connection with the pump, and at least 
12 feet of steel tubing should be used for boiler 
coils. The first power plant constructed by 
Mr. Harris contained a boiler coil 8 feet long, 
but after he had replaced this coil with one 12 
feet long, irrespective of the fact that the extra 
length of tube weighed a couple of ounces, the 
thrust was increased by nearly a half pound. 





. — 


■. 


Wmk 


WmM. 




An English steam power plant for model aeroplanes. 

Courtesy Flight. 



Model hydroaeroplane owned by V. E. Johnson, Model Edi¬ 
tor of Flight, England, equipped with an H. H. Groves 
steam power plant. This model is the first power driven— 
as far as can be learned—to rise from the surface of the 
water under its own power. Courtesy Flight. 


V 














STEAM POWER PLANTS 


121 


The principal parts used in Mr. Harris’s steam 
power plant was an engine of the H. H. Groves 
type, twin cylinder, bore with a piston 
stroke of J 4 ". The boiler was made from 12" 
of 3-16" x 20" G. steel tubing, weighing 10.5 
ounces. The blow lamp consisted of a steel 
tube, 5-32" x 22" G. wound round a carbide 
carrier for a nozzle. The tank was made 
of brass 5-1000" thick. The pump, 7-32" bore, 
stroke variable to J4", fitted with two non-re¬ 
turn valves (mushroom type) and was geared 
down from the engine 4.5 to 1. 

The Langley steam driven model, of which 
so much has been said, and which on one occa¬ 
sion flew a distance of one-half mile in 90 sec¬ 
onds, had a total weight of 30 lbs., the engine 
and generating plant constituting one-quarter 
of this weight. The weight of the complete 
plant worked out to 7 lbs. per h.p. The engine 
developed from 1 to h.p. A flash type 
boiler was used, with a steam pressure of from 
150 to 200 lbs., the coils having been made of 
copper. A modified naphtha blow-torch, such 


122 


MODEL AEROPLANES 


as is used by plumbers, was used to eject a blast 
or flame about 2000 Fahrenheit through the 
center of this coil. A pump was used for cir¬ 
culation purposes. With the best mechanical 
assistance that could be obtained at that date, 
it took Professor Langley one year to construct 
the model. 

About ten months after Langley’s results, 
some experiments were carried out by the 
French at Carquenez, near Toulon. The 
model used for the experiments weighed in 
total 70 lbs., the engine developing more than 
1 h.p. As in the Langley case, twin propellers 
were used, but instead of being mounted side by 
side, they were mounted one in front and the 
other behind. The result of these experiments 
compared very poorly with Langley’s. A 
flight of only 462 feet was made, with a dura¬ 
tion of a few seconds. The maximum velocity 
is stated to have been 40 m.p.h. The span of 
this model was a little more than 6 meters, or 
about 19 feet, with a surface of more than 8 
square meters, or about 80 square feet. 



An English hydroaeroplane of tractor design equipped with 
steam power plant. Courtesy Flight. 



On the right an English io oz. Compressed air driven bi¬ 
plane. On the left, the engine shown fitted with a simple 
speedometer for experimental purposes. Courtesy Flight. 















CARBONIC GAS ENGINE 


The six-cylinder carbonic gas engine de¬ 
scribed herewith is the product of Mr. Henry 
Rompel, Kansas City, Missouri. 

This is perhaps one of the most interesting 
of its kind to have been developed during 1916, 
and its appearance in the model aeroplane 
field adds weight to the claim that mechanical 
engines will soon replace the rubber strand as 
motive power for model aeroplanes. 

Mr. Rompers engine is of rotary, carbonic 
gas type, having six cylinders, a bore of $/§' 
and a stroke of 

The intake is derived through a rotary valve 
which also acts as a crank shaft bearing, there¬ 
by saving weight. 

The exhaust is accomplished by mechanically 

operated valves situated in the heads of the 

cylinders being opened by the aid of rocker 

123 


124 


MODEL AEROPLANES 


arms and push rods, which gain their timing 
from a cam placed on the crankshaft. 

To save weight in construction the crank¬ 
shaft, connecting rods, pistons and cylinders 
were made of telescopic tubing with a side wall 
of one thirty-second of an inch or less in thick¬ 
ness. 

The engine has a swing of 5J 4 " over all, 
weighs a little less than 8 ounces complete, 
and is operated on 1,500 pounds pressure (car¬ 
bonic gas) and at a speed of 3,500 to 3,700 
r.p.m. will develop about 1 horse power. 
While spinning a 17" propeller with a pitch 
of 20 inches it will deliver a thrust of 21 
ounces, and has a duration of 40 seconds. 
Two hundred and fifty-six pieces were em¬ 
bodied in its construction. 


V 



The Rompel six-cylinder carbonic gas engine 



























. 









































• • 




THE FORMATION OF MODEL 

CLUBS 

To form a model aeroplane club at least six 
interested persons are necessary. As soon as 
a place in which to hold meetings has been 
decided upon the club should proceed to elect 
a director whose duty should be to manage the 
affairs of the club. One of the first things to 
be considered is the name under which the 
club will operate; the custom is usually to adopt 
the name of the town or city in which the club 
is located, viz.: Concord Model Aero Club, 
Concord, Massachusetts, although it is the 
privilege of the majority of the members to 
choose a name such as they might feel will best 
benefit the purpose for which the club was or¬ 
ganized. As in the case of the Aero Science 
Club of America, this club was formed for the 

purpose of stimulating interest in model aero- 

125 


126 


MODEL AEROPLANES 


nautics and to help those who might become 
interested therein, not only in New York City 
but throughout the entire United States. 

When the matter of name and place has 
been settled the club should decide upon the 
course it is to follow, first by electing offi¬ 
cers and second by preparing a constitution 
and by-laws. In the case of clubs whose 
membership does not comprise more than six 
members, it does not seem desirable to have 
more than one officer, namely, a director, 
who might perform the duties of a president, 
treasurer and secretary until the club has 
reached a larger membership. In this way 
the members are enabled to concentrate upon 
the construction and flying of models and to 
engage in such other activities as to carry out 
the purpose for which the club was organized. 
However, the foregoing is merely a suggestion 
on the part of the writer, who by the way is a 
member of the Aero Science Club of America 
and formerly acted in the capacity of secretary 
to that club. 


FORMATION OF MODEL CLUBS 127 

Clubs whose membership totals more than 
twelve, however, should proceed to elect a Pres¬ 
ident, Treasurer and Secretary, all of whom 
must receive a vote of at least two-thirds of 
the membership. With clubs of this size a 
director is not needed as the affairs of the club 
are usually entrusted with the governing offi¬ 
cers, the President, Treasurer and Secretary. 
In as much as the constitution and by-laws are 
an important factor in the affairs of any 
model club, the governing officers, before men¬ 
tioned, should hold a private meeting, at the 
earliest moment whereat to frame a constitu¬ 
tion and set of by-laws embodying the pur¬ 
poses and policy of the club. When the pro¬ 
posed constitution and by-laws are completed 
they should be presented to the members for 
approval after which a copy should be given 
to every member. 

The following is a specimen of constitution 
and by-laws that might be used by any person 
or persons desiring to form a Model Aero 
Club: 


128 


MODEL AEROPLANES 


CONSTITUTION AND BY-LAWS OF A MODEL 
AEROPLANE CLUB 

Article i. Name. The name of this 

club will be known as The.Model 

Aero Club. 

Purpose. The object of this club shall be 
to study and increase the interest in the science 
of aeronautics in every way possible and to 
realize this object, shall construct and fly model 
aeroplanes, gliders and man carrying ma¬ 
chines. 

Further, Contests shall be held for model 
aeroplanes and prizes awarded to the winners 
thereof. And as a further step in the ad¬ 
vancement of this art, meetings, lectures, 
discussions, debates and exhibitions will be 
held. 

Article 2. Membership. Any person 
may become a member of this club provided 
his application receives the unanimous ap¬ 
proval of the majority of members, or is passed 
upon by the membership committee. A mem- 



FORMATION OF MODEL CLUBS 129 

ber may resign his membership by written com¬ 
munication to the secretary who shall present 
it to the membership committee to be passed 
upon. 

Article 3. Officers. The officers of this 
organization shall be a President, Vice-presi¬ 
dent, Secretary and Treasurer and a board of 
governors to consist of said officers. The 
president and vice-president shall constitute 
the executive committee of the board of gov¬ 
ernors, with full powers to act for them in the 
affairs of the club. The election of officers 
shall take place at the first meeting held dur¬ 
ing the month of.of each year and 

shall hold office for one year. In the event 
of a vacancy in the office of the President the 
Vice-president or next highest officer present 
shall preside. Any other vacancy shall be filled 
by an officer temporarily appointed by the Pres¬ 
ident. The President shall preside at all meet¬ 
ings of the club and of the board of governors, 
and shall perform such other duties as usually 
pertain to that office. The President shall 



130 


MODEL AEROPLANES 


have full authority to appoint committees or 
boards as may be necessary to further the in¬ 
terests of the club. 

The Secretary shall keep a record of all 
meetings of the club, board of governors and 
committees and shall use the seal of the club 
as may be directed by the executive commit¬ 
tee. Further, he shall issue notices to officers 
and members of all special meetings and per¬ 
form such other duties as may be assigned him 
by the constitution, by the club or by the board 
of governors. 

The Treasurer shall have charge of the 
funds of the club, receive all moneys, fees, dues, 
etc.; pay all bills approved by the board of gov¬ 
ernors, and preserve all proper vouchers for 
such disbursements. 

RULES FOR CONTESTS 

We now come to the matter of contests. As 
there are many different types of models so 
must there be rules to correspond to avoid mis¬ 
understandings, and until the club has reached 


FORMATION OF MODEL CLUBS 131 

the stage where it may decide upon a partic¬ 
ular set of rules under which its members 
should participate perhaps the following set 
of rules, applicable to contests for hand 
launched models, can be adopted. In so far 
as there are different rules for different con¬ 
tests, namely, hand launched, R. O. G. and 
R. O. W. and mechanical driven, the following 
rules are used only in connection with contests 
for hand launched models; rules for other con¬ 
tests follow: 

RULES 

A contest to be official must have at least five 
contestants. 

Each contestant must abide by the rules of 
the contest and decision of the judges. 

Each contestant must register his name, age, 
and address before the event. 

Each contestant must enter and fly models 
made by himself only. 

Trials to start from a given point indicated 
by the starter of the trials, and distance to be 
measured in a straight line from the starting 


i3 2 


MODEL AEROPLANES 


point to where the model first touches the 
ground, regardless of the curves or circles it 
may have made. Each contestant must have 
his models marked with his name and number 
of his models (i, 2, 3, etc.), and each model 
will be entitled to three official trials. Contest¬ 
ant has the privilege of changing the planes 
and propellers as he may see fit, everything 
to be of his own construction, but only three 
frames can be used in any contest. If in the 
opinion of the board of judges there are too 
many entries to give each one nine flights in 
the length of time fixed, the judges have the 
power to change that part of rule No. 6 to the 
following: 

“Six flights or less, as circumstances may 
require, will be allowed to each contestant, 
which can be made with one model or any one 
of three entered; all of his own construction; 
due notice must be given to each contestant of 
the change/’ 

No trial is considered as official unless the 
model flies over 100 feet from the start- 


FORMATION OF MODEL CLUBS 133 

ing point. (The qualifying distance can be 
changed by agreement between the club and 
the starter provided the entrants are notified.) 
Should the rubber become detached from the 
model, or the propeller drop off during the 
trial, the trial is counted as official, provided 
the model has covered the qualifying distance. 
No matter what may happen to the model after 
it has covered the qualifying distance the flight 
is official. Contests should cover a period of 
three hours, unless otherwise agreed. 

No contestant shall use the model of another 
contestant, although the former may have 
made it himself. 

The officials should be: a starter, measurer, 
judge and scorer; also three or four guards to 
keep starting point and course clear. The 
first three officials shall, as board of judges, 
decide all questions and disputes. A space 25 
feet square (with stakes and ropes) should be 
measured off for officials and contestants, to¬ 
gether with an assistant for each contestant. 
All others must be kept out by the guards and a 


134 


MODEL AEROPLANES 


space kept clear (at least 25 feet) in front of 
the starting point, so a contestant will not be 
impeded in making his trial. 

Each official should wear a badge, ribbon or 
arm band designating his office, and must be 
upheld in his duties. 

HANDICAPS 

At the discretion of the club there may be 
imposed a handicap for club events as follows: 
A contestant in order to win must exceed his 
last record with which he won a prize. 

COMBINATION AND DURATION EVENTS 

First, second and third records to count. 
Lowest number of points to win. For exam¬ 
ple: 

A may have 1st in distance and 2nd in dura¬ 
tion, 3 total points. 

B may have 3rd in distance and 1st in dura¬ 
tion, 4 total points. 

C may have 2nd in distance and 3rd in du¬ 
ration, 5 total points. 

Accordingly A wins. 


FORMATION OF MODEL CLUBS 135 


R. O. G. CONTESTS 

(Rising from the Ground) 

Models to be set on the ground and allowed 
to start off without any effort on the part of 
the contestant. Models should rise from the 
ground before reaching a predetermined mark, 
no flight to be considered unless it does so. 
Contestant may start at any length back from 
the mark, but the distance is to be measured 
only from the mark. 

MECHANICALLY DRIVEN MODEL CONTESTS 

For duration, or distance, contests for me¬ 
chanically driven models might be held under 
the same ruling that applies to R. O. G. models. 
But owing to the many types of engines used 
in mechanically driven models, definite rules 
for the holding of such a contest must be left 
to the discretion of the club or contestants. 

EVENTS OPEN TO ALL 

These events are open to all, with no handi¬ 
caps to be imposed on either club members or 
others. 


136 


MODEL AEROPLANES 


INTER-CLUB MODEL AEROPLANE 
TOURNAMENTS 

(Prizes to be determined by contesting clubs) 

The tournament to consist of five events as 
follows: 

Models launched from hand. 
Models launched from hand. 


Duration: 
Distance: 
Duration: 
R. O. G. 

Distance: 
R. O. G. 
Duration: 


Models launched from ground. 


Models launched from ground. 


Models launched from water. 


R. O. W. 

Dates for inter-club contest should be ar¬ 
ranged for at least three weeks prior to date 
of first contest, to allow ample time for the 
construction of special models and elimination 
trials. 

In event of inclement weather the contest 
to take place the week following (each contest 
following to be set one week ahead), or at any 
time that may be determined by a committee 
appointed by the contesting clubs. 


FORMATION OF MODEL CLUBS 137 

Each competing club must be represented by 
a team of three contestants and one non¬ 
competitor, who will act as judge in conjunc¬ 
tion with the judges from the other clubs, and 
a manager selected by the judges who will 
supervise over the entire tournament and is¬ 
sue calls for meetings. (Substitutes should 
also be selected for any possible vacancy.) 

Meetings of the judges of the competing 
clubs should be held at some designated place, 
at which time dates and general details shall 
be arranged, and between events there should 
be a meeting called, for general discussion re¬ 
garding the recent event, receive protests and 
suggestions and to announce officially the re¬ 
sult of the contest. 

The manager shall have control of the va¬ 
rious events, assisted by the judges and they 
shall decide all disputes that may arise, and 
act as scorers and timers, as well. 

Each flyer will be allowed but one model 
and shall be entitled to three official flights, but 
he shall be permitted to make any repairs or 


138 


MODEL AEROPLANES 


replace any broken parts. No contestant shall 
be privileged to fly a model not of his own con¬ 
struction. Each event shall close when all the 
contestants have made three official flights, or 
when three hours’ time has elapsed. 


WORLD’S MODEL FLYING 
RECORDS 

(Twin Propeller Pusher Type Models) 

MONOPLANE 

Year 1917. Ward Pease (America), rise off ground 
distance 3364 feet. 

Year 1916. Thomas Hall (America), hand launched, 
distance 5537 feet. 

Year 1917. Donovan Lathrop (America), hand 
launched, duration, 5 minutes. 

Year 1917. Emil Laird (America), 18 inch type 
model, distance 750 feet. 

Year 1915. Wallace A. Lauder (America), hand 
launched, distance 3537 feet. 

Year 1915. Wallace A. Lauder (America), hand 
launched, duration 195 seconds. 

Year 1914. Fred Watkins (America), rise off 
ground, distance 1761 feet. 

Year 1914. J. E. Louch (England), rise off ground, 
duration 169 seconds. 

Year 1915. E. C. Cook (America), rise off water, 
duration 100 seconds. 

i39 


140 


MODEL AEROPLANES 


(Twin Propeller Tractor Type) 

MONOPLANE 

Year 1913. Harry Herzog (America), rise off water, 
duration 28 seconds. 

(Twin Propeller Pusher Type) 
biplane 

Year 1915. A. H. Wheeler (America), rise off 
ground, duration 143 seconds. 

(Single Propeller Pusher Type) 

MONOPLANE 

Year 1914. J. E. Louch (England), hand launched, 
duration 95 seconds. 

Year 1914. W. E. Evans (England), rise from 

ground, distance 870 feet. 

Year 1914. J. E. Louch (England), rise from 

ground, duration 68 seconds. 

Year 1914. L. H. Slatter (England), rise from water, 
duration 35 seconds. 

(Single Propeller Tractor Type) 

MONOPLANE 

Year 1915. D. Lathrop (America), hand launched, 
distance 1039 feet. 

Year 1915. D. Lathrop (America), hand launched, 
duration 240 seconds. 

Year 1914. C. D. Dutton (England), rise from 

ground, distance 570 feet. 

Year 1914. J. E. Louch (England), rise from ground, 
duration 94 seconds. 


FLYING RECORDS 


141 

Year 1915. L. Hittle (America), rise from water, 
duration 116 seconds. 

(Single Propeller Tractor Type) 
biplane 

Year 1915. Laird Hall (American), rise from ground, 
duration 76 seconds. 

(Flying Boat Type) 

MONOPLANE 

Year 1915. Robert La Tour (America), rise from 
water, duration 43 seconds. 

(Flying Boat Type) 
biplane 

Year 1914. C. V. Obst (America), rise from water, 
duration 27 seconds. 

( 

(Mechanical Driven Model) 

Year 1914. D. Stanger (England), rise from ground, 
duration 51 seconds. 

(All British records are quoted from Flight ) 


DICTIONARY OF AERONAUTICAL 

TERMS 

A 

Aerodrome—A tract of land selected for flying pur¬ 
poses. 

Aerodynamics —The science of Aviation, literally the 
study of the influence of air in motion. 

Aerofoil —A flat or flexed plane which lends support 
to an aeroplane. 

Aeronaut —One engaged in navigating the air. 

Aeronautics —The science of navigating the air. 

Aeroplane —A heavier than air machine supported by 
one or more fixed wings or planes. 

Aerostatics —The science of aerostation, or of buoy¬ 
ancy caused by displacement, ballooning. 

Aerostation —The science of lighter than air or gas- 
born machines. 

Aileron —The outer edge or tip of a wing, usually 
adjustable, used to balance or stabilize. 

Airship —Commonly used to denote both heavier and 
lighter than air machines; correctly a dirigible 
balloon. 

Angle of Incidence —The angle of the wing with 
the line of travel. 


142 


DICTIONARY OF TERMS 


143 


AreX—I n the case of wings, the extent of surface 
measured on both the upper and lower sides. An 
area of one square foot comprises the actual sur¬ 
face of two square feet. 

Aspect Ratio —The proportion of the chord to the 
span of a wing. For example if the wing has a 
span of 30 inches and a chord of 6 inches the 

span 

aspect ratio will be 5 or 77;-, 

r J Chord. 

Automatic Stability —Stability secured by fins, the 
angle of the wings and similar devices. 

Aviator —One engaged in Aviation. 

Aviation —The science of heavier than air machines. 

Angle of Blade —The angle of the blade of a propeller 
to the axis of the shaft. 


B 

Balancer —A plane or other part intended for lateral 
equilibrium. 

Bearing Block —Used in connection with the mount¬ 
ing of propellers on model aeroplanes. Made 
from wood and metal. 

Brace —Strip of bamboo or other material used to join 
together the frame side members. Also used in 
joining other parts of a model. 

Biplane —An aeroplane or model aeroplane with two 
wings superposed. 

Body —The main framework supporting the wing or 
wings and the machinery. 



MODEL AEROPLANES 


144 

Banking —The lateral tilting of an aeroplane when 
taking a turn. 

C 

Camber— The rise of the curved contour of an arched 
surface above the Chord Line. 

Center of Gravity —The point at which the aero¬ 
plane balances. 

Center of Pressure— The imaginary line beneath the 
wing at which the pressure balances. 

Chassis (Carriage)— The part on which the main 
body of an aeroplane or model aeroplane is sup¬ 
ported on land or water. 

Chord —The distance between the entering and trail¬ 
ing edges of a wing. 

D 

Deck— The main surface of a biplane or multiplane. 

Directional Control— The ability to determine the 
direction of the flight of an aeroplane. 

Dirigible— A balloon driven by power. 

Dope —A coating for wings. 

Down Wing —With the wind. 

Drift— The resistance of the wing to the forward 
movement. 

Dihedral Angle —The inclination of the wings to each 
other usually bent up from the center in the form 
of a flat V. 

E 

Elevator —The plane or wing intended to control the 
vertical flight of the machine. 


DICTIONARY OF TERMS 145 

Engine —A contrivance for generating driving power. 

Engine Base —Main stick used for frame of single 
stick model. 

Engineer —One who controls the power, driving the 
machinery. 

Entering Edge or Leading Edge —Front edge or 
edge of the surface upon which the air impinges. 

Equilibrator —A plane or other contrivance which 
makes for stability. 

\ F 

Fin —A fixed vertical plane. 

Flexed —A wing is said to be flexed when it curves 
upward forming an arc of a circle. 

Flying Stick —Name applied to ordinary A type and 
single stick models. 

Flying Machine —Literally a form of lighter than 
air craft; a gas-borne airship. 

Flying Boat —A hull or large float used in connection 
with an aeroplane to enable its rising from and 
alighting upon the surface of the water. 

Frame —A single or double stick structure to which all 
parts of a model are attached. Three or more 
sticks are sometimes employed in the construction 
of a frame. However, the usual number is two, 
joined together in the form of letter “A.” 

Frame Hooks —The looped ends of a piece of wire at¬ 
tached to the point of the frame to accommodate 
the S hooks attached to the rubber strands. 

Frame Side Members —Two main sticks of an A type 
frame. 


146 MODEL AEROPLANES 

Fuselage —The body or framework of an aeroplane. 

G 

Glider— An aeroplane without motive power. 

Guy—A brace, usually a wire or cord used for tuning 
up the aeroplane. 

Gross Weight —The weight of the aircraft, compris¬ 
ing fuel, lubricating oils and the pilot. 

Gyroscope —A rotating mechanism for maintaining 
equilibrium. 

Gap— The vertical distance between the superposed 
wings. 

H 

Hangar —A shed for housing an aeroplane. 

Harbor —A shelter for aircraft. 

Heavier than Air—A machine weighing more than 
the air it displaces. 

Hellicopter— A flying machine in which propellers 
are utilized to give a lifting effect by their own di¬ 
rect action on the air. In aviation the term im¬ 
plies that the screw exerts a direct lift. 

Helmsman —One in charge of the steering device. 

Hydroaeroplane —An aeroplane with pontoons to en¬ 
able its rising from the surface of the water. 
Known as hydro in model circles. 

K 

Keel —A vertical plane or planes arranged longitudi¬ 
nally either above or below the body for the pur¬ 
pose of giving stability. 


DICTIONARY OF TERMS 


147 


L 

Lateral Stability— Stability which prevents side mo¬ 
tion. 

Loading —The gross weight divided by the supporting 
area measured in square feet. 

Longitudinal Stability —Stability which prevents 
fore and aft motion or pitching. 

Longerons— Main members of the fuselage. Some¬ 
times called longitudinals. 

M 

Mast —A perpendicular stick holding the stays or 
struts which keep the wings rigid. 

Model Aeroplane—A scale reproduction of a man¬ 
carrying machine. 

Mechanical Power— A model driven by means other 
than rubber strands such as compressed air, steam, 
gasoline, spring, electricity and so forth is termed 
a mechanical driven model. The power used is 
termed mechanical power. 

Motive Power —In connection with model aeroplanes 
a number of rubber strands evenly strung from the 
propeller shaft to the frame hooks which while 
unwinding furnish the necessary power to propel 
the model. 

Main Beam —In connection with model aeroplanes 
a long stick which is secured to the under side of 
the wing frame at the highest point in the curve 
of the ribs adding materially to the rigidity of the 
wing. 


148 MODEL AEROPLANES 

Monoplane —An aeroplane or heavier than air ma¬ 
chine supported by a single main wing which may 
be formed of two wings extending from a central 
body. 

Multiplane —An aeroplane with more than four 
wings superposed. 

N 

Nacelle —The car of a dirigible balloon, literally a 
cradle. Also applied to short body used in connec¬ 
tion with aeroplanes for the accommodation of the 
pilot and engine. 

Net Weight —Complete weight of the machine with¬ 
out pilot, fuel or oil. 

O 

Ornithopter —A flapping wing machine which has 
arched wings like those of a bird. 

Orthogonal —A flight maintained by flapping wings. 

Outriggers —Members which extend forward or rear¬ 
ward from the main planes for the purpose of 
supporting the elevator or tail planes of an aero¬ 
plane. 

P 

Plane —A surface or wing, either plain or flexed, em¬ 
ployed to support or control an aeroplane. 

Pilot —One directing an aeroplane in flight. 


DICTIONARY OF TERMS 


149 

Pitch— Theoretical distance covered by a propeller in 
making one revolution. 

Propeller —The screw used for driving an aeroplane. 

Propeller Bearings— Pieces of bronze tubing or strips 
of metal formed to the shape of the letter “L” 
used to mount propellers. Also made from blocks 
of wood. 

Propeller Blank —A block of wood cut to the design 
of a propeller. 

Propeller Spar(s)— The heavy stick or sticks upon 
which the bearing or bearings of a single or twin 
propeller model are mounted. 

Propeller Shaft —A piece of wire which is run 
through the hub of the propeller and tubing in 
mounting the propeller. 

Pylon —Correctly, a structure housing a falling weight 
used for starting an aeroplane, commonly a turn¬ 
ing point in aeroplane flights. 

Pusher —An aeroplane with the propeller or propellers 
situated in back of the main supporting surfaces. 


Q 

Quadruplane —An aeroplane with four wings super¬ 
posed. 

R 

Rudder—A plane or group of planes used to steer an 
aeroplane. 

Runner —Strip beneath an aeroplane used for a skid. 


150 MODEL AEROPLANES 

Running Gear or Landing Gear —That portion of 
the chassis consisting of the axle, wheels and shock 
absorber. 

Rib —Curved brace fastened to the entering and trail¬ 
ing edges of a wing. 


S 

Scale Model —A miniature aeroplane exactly repro¬ 
ducing the proportions of an original. 

Spar —A mast strut or brace. 

Side Slip —The tendency of an aeroplane to slide or 
slip sideways when too steep banking is attempted. 

Stability —The power to maintain an even keel in 
flight. 

Starting Platform —A runway to enable an aero¬ 
plane to leave the ground. 

Surface Friction —Resistance offered by planes or 
wings. 

Slip —The difference between the distance actually 
traveled by a propeller and that measured by the 
pitch. 

Soaring Flight —A gliding movement without ap¬ 
parent effort. 

Sustaining Surface —Extent of the wings or planes 
which lend support to an aeroplane. 

Span (Spread) —The dimension of a surface across 
the air stream. 

Streamline —Exposing as little surface as possible to 
offer resistance to air. 


DICTIONARY OF TERMS 


151 

Skids —In connection with model aeroplanes, steel 
wires or strips of bamboo allowed to extend below 
the frame to protect the model in landing and to 
permit its rising off the ground or ice. 

S or Motor Hooks —A piece of wire bent in a double 
hook to resemble the letter “S.” One end to 
be attached to the frame hook, the other serving 
as accommodation for the rubber strands. 

T 

Tail—T he plane or planes, both horizontal and verti¬ 
cal, carried behind the main planes. 

Tandem —A11 arrangement of two planes one behind 
the other. 

Thrust —The power exerted by the propeller of an 
aeroplane. 

Tension —The power exerted by twisted strands of 
rubber in unwinding. 

Tractor —An aeroplane with the propeller situated be¬ 
fore the main supporting surfaces. 

Triplane —An aeroplane with three wings superposed. 

Trailing Edge—T he rear edge of a surface. 

Torque —The twisting force of a propeller tending to 
overturn or swerve an aeroplane sideways. 

U 

Up Wind— Against the wind. 

W 

Wake—T he churned or disturbed air in the track of a 
moving aeroplane. 


152 MODEL AEROPLANES 

Wash —The movement of the air radiating from the 
sides of an aeroplane in flight. 

Wings —Planes or supporting surfaces, commonly a 
pair of wings extending out from a central body. 

Winder —An apparatus used for winding two sets of 
rubber strands at the same time in opposite direc¬ 
tions or one at a time. Very often made from an 
egg beater or hand drill. 

Warping —The springing of a wing out of its normal 
shape, thereby creating a temporary difference in 
the extremities of the wing which enables the wind 
to heel the machine back again into balance. 

ABREVIATIONS 

H. P. Horse Power. 

R. P. M. Revolutions per minute. 

H. L. Hand launched. 

R. O. G. Rise off ground model. 

R. O. W. Rise off water model. 

M. P. H. Miles per hour. 


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